President Barack Obama and European leaders are threatening new sanctions on Russia after pro-Russian rebels launched a deadly rocket attack on the Ukrainian port city of Mariupol.
On a state visit to India Sunday, Obama said he would "ratchet up" pressure on Moscow in the wake of the attack the day before that killed at least 30 people and injured more than 80 others when the rockets slammed into a market and apartment buildings.
"We are deeply concerned about the latest break in the (Ukrainian) cease-fire and the aggression that these separatists, with Russian backing, Russian equipment, Russian financing, Russian training and Russian troops, are conducting," Obama said.
"We will continue to take the approach that we have taken in the past, which is to ratchet up the pressure on Russia, and I will look at all additional options that are available to us short of military confrontation and try to address this issue," he added.
EU president condemns appeasement
Some European leaders have recently talked of easing economic sanctions against Moscow. But Donald Tusk, the former Polish prime minister who now serves as European Union president, tweeted in a message, "Once again, appeasement encourages the aggressor to greater acts of violence. Time to step up our policy based on cold facts, not illusions."
Ukraine President Petro Poroshenko said that radio and telephone conversations intercepted by Kyiv prove that Russian-backed separatists were responsible for the Mariupol attack.
Mariupol lies between Russia and the Russian-annexed Crimean peninsula. Heavy fighting in the region in the fall raised fears that pro-Russia separatists would try to capture the city as part of a push to create corridor that would allow Russia to access Crimea by land. Currently, it can only do so by air and sea.
Rebels launched new attacks on Sunday against government positions elsewhere along the front line that winds through the two rebel-dominated eastern provinces of Donetsk and Luhansk, the Ukrainian military said.
Lavrov blames Kyiv for escalation
Meanwhile, Russian Foreign Minister Sergei Lavrov, speaking separately by phone with EU foreign policy chief Federica Mogherini and U.S. Secretary of State John Kerry, said Sunday that Kyiv's forces were responsible for increased fighting in recent days in eastern Ukraine.
Lavrov told Mogherini Sunday that Moscow wants the EU to pressure Ukraine to negotiate with the rebels to implement a frequently broken cease-fire agreed to last September.
Kerry told Lavrov that the U.S. was ready to participate in serious efforts to settle the conflict, but made clear that "Russia will be judged by its actions and that the costs to Russia will only increase if attacks continue," the State Department said.
In the wake of the Mariupol attack, Mogherini said she is calling an urgent meeting Thursday of EU foreign ministers to discuss the new violence in Ukraine and to map out the bloc's response.
Poroshenko meets with security officials
After the Mariupol attack, Poroshenko vowed to protect Ukrainian territory. He cut short his trip to Saudi Arabia for the late King Abdullah's funeral to chair an emergency meeting of Ukraine's security council.
Poroshenko spoke about the situation in a telephone call Saturday with U.S. Vice President Joe Biden, who condemned the attacks, saying they were "initiated by Russia-backed separatists."
The two officials also "expressed grave concern over Russia's blatant disregard for its commitments under the September Minsk agreement and unilateral escalation of the conflict, and agreed to work with international partners to ensure that the costs continue to rise on Russia for its aggressive actions against Ukraine," according to a readout of the call published by the White House.
Latvia, which currently holds the European Union's rotating presidency, called for the bloc to hold an emergency meeting with its foreign ministers to discuss the situation.
NATO Secretary-General Jens Stoltenberg said the offensive "is in utter disregard of the cease-fire."
Stoltenberg said Russian troops have been supporting rebel operations with surface-to-air missiles and "advanced multiple rocket-launcher systems."
Both Stoltenberg and Mogherini urged Russia to stop providing the rebels with military and financial support. Mogherini called on Russia to use its influence to halt the offensive.
Russia said it has not sent troops into Ukraine, and any Russians there are volunteers. NATO said that is nonsense.
“I strongly urge Russia to stop its military, political and financial support for the separatists, stop destabilizing Ukraine and respect its international commitments,” Stoltenberg said.
Dozens of mourners held a minute of silence and lit candles in Kyiv's Independence Square Saturday evening to commemorate those killed in Mariupol.
Ukraine military spokesman Andriy Lysenko said Sunday rebel shelling had killed an undetermined number of civilians and damaged 60 residential buildings in Mariupol. He said there was no electricity or heat in the city of 25,000 people.
Lysenko also said four Ukrainian servicemen were killed and 17 wounded over the past 24 hours.
The Organization for Security and Cooperation's monitoring mission said Saturday that the Grad and Uragan rockets that hit Mariupol were fired from areas under rebel control.
The OSCE said its Permanent Council would meet Monday in Vienna “in light of the rapid deterioration of the situation in eastern Ukraine.”
In Mariupol on Sunday, emergency workers disposed of rocket fragments left by the attack. Police said two unexploded rockets were found in a bank and an apartment building.
U.N. refugee agency workers handed out blankets to people left homeless or without heat because of the shelling, which hit schools, homes and shops.
“The city is in shock,” Mariupol resident Yelena Khorshenko said by telephone. “The streets are empty, and people are boarding up their windows and preparing for the worst.”
Some material for this report came from Reuters, AP and AFP.