U.S. President Barack Obama said that Russian President Vladimir Putin must recognize and work with Ukraine's newly-elected government and stop "provocations" along its border, or face tougher sanctions from members of the Group of Seven nations.
All sides agreed Russia should change its behavior, and they joined in threatening to slap new sanctions that would target entire sectors of the Russian economy.
“We will have a chance to see what Mr. Putin does over the next two, three, four weeks, and if he remains on the current course, then we've already indicated the kinds of actions that we're prepared to take,” Obama said at a joint news conference with British Prime Minister David Cameron at the end of a G7 summit in Brussels, Belgium.
“Russia needs to seize that opportunity,” Obama said. “Russia needs to recognize that President-elect [Petro] Poroshenko is the legitimately elected leader of Ukraine and engage the government in Kyiv.”
Obama emerged from two days of meetings with the G7, saying it was a chance for the gathered leaders to make sure they are in “lockstep” on a strategy going forward in uncertain times in Ukraine.
He and Cameron both praised the united front that the U.S. and Europe has maintained in dealing with Russia and the crisis in Ukraine.
"What has been striking has been the degree of solidary between the United States and Europe in this crisis," Obama said. "I've been heartened by the steadfastness of Europe so far."
U.S. President Barack Obama walks with Italian Prime Minister Matteo Renzi, Canadian Prime Minister Stephen Harper, German Chancellor Angela Merkel, British Prime Minister David Cameron, French President Francois Hollande, European Commission President Jose Manuel Barroso and Japanese Prime Minister Shinzo Abe after a G7 group photo in Brussels, June 5, 2014.
U.S. President Barack Obama laughs as he looks at British Prime Minister David Cameron during a G7 session in Brussels, June 5, 2014.
U.S. President Barack Obama meets with Belgian King Philippe and Belgian Prime Minister Elio Di Rupo at the Royal Palace of Brussels, June 4, 2014.
U.S. President Barack Obama and Polish President Bronislaw Komorowski show the peace sign at a Freedom Day event at Royal Square in Warsaw, June 4, 2014.
U.S. President Barack Obama speaks during a ceremony marking the "Freedom Day" anniversary in Warsaw's Castle Square, June 4, 2014.
U.S. President Barack Obama speaks during a ceremony marking the Freedom Day anniversary in Castle Square in Warsaw, June 4, 2014.
U.S. President Barack Obama shakes hands with Ukraine's President-elect Petro Poroshenko during their meeting in Warsaw, June 4, 2014.
U.S. President Barack Obama and Polish President Bronislaw Komorowski walk away after a group photo with Central and Eastern European Leaders in Warsaw, June 3, 2014.
U.S. President Barack Obama is welcomed by Polish Prime Minister Donald Tusk in Warsaw, June 3, 2014.
U.S. President Barack Obama and Poland's President Bronislaw Komorowski walk to make statements after meeting U.S. and Polish troops at an event featuring F-16 fighter jets in Warsaw, June 3, 2014.
Obama said he understands the real economic consequences on countries that have extensive trade ties with Russia, but indicated those have to be weighed against the values and principles that Russia has violated.
“The choice is clear: Europeans have to stand up for those ideals and principles even if it creates some economic inconvenience," he said.
The president said the U.S. is looking at sanctions that would maximize the consequences on Russia but minimize the adverse effects on the economies of G7 nations.
Obama urged Putin to “enter into a dialogue” with Poroshenko, who is being inaugurated Saturday after winning the May 25 election.
Cameron, who will meet with Putin later Thursday, said he plans to tell the Russian president that Russia's actions in Ukraine are unacceptable and at odds with G7 leaders' democratic values.
The prime minister said he plans to discuss with Putin the demands outlined by the G7 members as a whole -- that Russia respect the results of Ukraine's presidential election, stop the flow of fighters and weapons to the eastern part of the country, and completely withdraw troops from its border with Ukraine
If Putin does not meet the demands, Russia, whose economy has already begun to suffer from present sanctions, will possibly face harsher, sectoral sanctions, Cameron said.
In other questions, Obama also said he had "expressed some concerns" to France about its sale of warships to Russia during this period.
“I think it would have been preferable to press the pause button," Obama said in response to a question about the decision to go ahead with the sale of French Mistral warships despite events in Ukraine.
France has come under pressure from some European allies to pull the plug on the 1.2-billion-euro deal on the grounds Russia could use the Mistral-class helicopter carriers to threaten its Black Sea neighbors.
France agreed to the sale under a 2011 contract, with the first vessel due in October and the second in 2015.
The Mistral, the second-largest ship in the French navy, is a high-seas military base that can transport up to 16 helicopters, four landing craft, 60 armed vehicles and some 700 troops.
Other G7 action
In other G7 action, the world's leading industrialized nations vowed on Thursday to seal a series of free-trade deals that would radically change the shape of global commerce despite rising popular opposition.
Leaders of the G7 committed themselves to eight far-reaching accords that would encompass more than 80 percent of the world's economy but that effectively sideline China and Russia and have met with protests, particularly in Europe.
In the most ambitious round of liberalization since the demise of the Doha round of global trade talks, the leaders of Britain, France, Germany, Italy, Japan, Canada and the United States want to create a market of almost a billion people and set world trade rules that the rest may have to follow.
An EU-U.S. deal alone could generate $100 billion in additional economic output a year on both sides of the Atlantic.
The G7 also gave their backing on Thursday to a new global deal on climate change in 2015.
Earlier this week, the United States announced a plan to cut emissions from power plants by 30 percent by 2030, which will run into domestic opposition, prompting the European Union into a defense of its own record.
China, the world's biggest emitter of greenhouse gasses, also gave a hint that it would set some kind of cap on its emissions.
A draft of the G7 communique seen by Reuters said the G7 nations remained committed to low-carbon economies and limiting temperature rises to 2 degrees Celsius above pre-industrial levels, the limit scientists say can prevent the most devastating effects of climate change.
And the G7 offered the EU support with its efforts to make its energy supplies more secure, promising to “complement the efforts of the European Commission to develop emergency energy plans for winter 2014-2015”.
In Europe, the quest for energy security in the face of threats from Russia that it could disrupt supplies of gas pumped through Ukraine, has knocked the climate debate down the agenda.
But addressing the G7 in Brussels, Commission President Jose Manuel Barroso said the two issues went “hand in hand.”
EU nations said domestic, renewable sources, such as solar and wind, can reduce the need for fossil fuel imports from nations such as Russia, while Poland, which relies on polluting coal, said coal is a reliable, domestic fuel source.
Obama's aim at this G7 summit was to further isolate Russia and galvanize support among western European nations for tougher sanctions in case it is necessary to apply them.
The summit was originally scheduled as a G-8 to be held in the Russian Black Sea resort of Sochi, with Putin as host.
After Russia annexed Crimea, the economic powers revoked the Russian leader's invitation and moved the meeting to Brussels.
"Originally of course our summit was supposed to be in Sochi, but after Russia's actions in Ukraine, our nations united quickly around a common strategy. We suspended Russia from the G8, and we canceled the Sochi meeting, making this the first G7 held without Russia in some 20 years," Obama said on Thursday.
During the visit, though, it became clear that not all G-7 leaders were as eager as Obama to isolate Putin.
The Russian president and Obama are both attending D-Day commemorations in France Friday, but there are no plans for them to meet.
Other G-7 leaders, however, are meeting privately with Putin, including French President Francois Hollande and German Chancellor Angela Merkel.
Later Thursday, Obama headed to Paris and was to attend a dinner with Hollande, who had planned a second dinner with Putin later the same night.
The meetings will come at a ceremony in Normandy, France to mark the 70th anniversary of the allied D-Day invasion against Nazi forces in World War II.
Kerry, Lavrov meet
The top U.S. and Russian diplomats met in Paris on Thursday, and agreed that Ukraine should be a bridge between Russia and the West and not be a “pawn” in a power struggle.
"President-elect Poroshenko has made it clear that he wants to reach out to all of the people of Ukraine, and he intends to make a major effort to bring the country together," U.S. Secretary of State John Kerry said before meeting with Russian Foreign Minister Sergey Lavrov.
"This is an opportunity we hope for Russia, the United States, and others ... to make a Ukraine that is strong economically, whose sovereignty is respected, whose independence is respected, but which clearly is not the pawn in a tug-of-war between other nations ... [and] able to act as a bridge between east and west with trade, with engagement between all parties," Kerry said.
“We would like to see Ukraine peaceful, stable. A place for all those who live in Ukraine ... to be feeling equal, respected, and listened to, living in peace being a bridge, not being a pawn,” Lavrov said.
Luis Ramirez contributed to this report from Brussels, some information provided by Reuters, AFP and AP.