The United Nations secretary-general says any confirmed use of chemical weapons in Syria would be an “outrageous war crime,” and the perpetrators must be brought to justice.
Ban Ki-moon urged the U.N. Security Council Tuesday to “unite and develop an appropriate response” if U.N. investigators confirm that chemical weapons were used.
“This is a larger issue than the conflict in Syria. This is about our collective responsibility to humankind,” he said.
However, Ban said, any use of force to punish those responsible for a chemical attack that killed more than 1,400 Syrians last month must have U.N. authorization to be legal.
Congressional leaders offer backing
Ban spoke as President Barack Obama and his top foreign-policy and defense officials were working to build domestic support for a U.S. military strike on the Syrian government. The U.S. says Syrian President Bashar al Assad was behind the nerve-gas attack on August 21.
After a White House meeting Tuesday, top U.S. lawmakers from both parties said they will support a U.S. strike.
John Boehner, leader of the Republican Party in the House of Representatives, says the United States has the capability to stop Syrian President Bashar al-Assad.
Boehner, who frequently clashes with Obama, mostly on domestic issues, urged colleagues to do the same.
"We have enemies around the world that need to understand we are not going to tolerate this type of behavior," he said.
Nancy Pelosi, who leads Obama's Democratic Party in the House, said Syria's use of chemical weapons was outside of the "circle of civilized behavior." She said the United States must respond.
The Syrian government has denied that its military has used chemical weapons.
Obama said he is asking Congress to approve a "proportional, limited" military response that would send a "clear message" to Assad's regime and any other country interested in "testing international norms."
Sending 'a clear message' to Syria
"We recognize that there are certain weapons that when used can not only end up resulting in grotesque deaths but also can end up being transmitted to non-state actors, can pose a risk to allies and friends of ours, like Israel, like Jordan, like Turkey," he said as he headed into the meeting with congressional leaders.
Obama said the U.S. had a "broader strategy" that involves upgrading the capabilities of the Syrian opposition.
A day of intense outreach to the Congress included a appearances by Secretary of State John Kerry, Defense Secretary Chuck Hagel and the Chairman of the Joint Chiefs of Staff, General Martin Dempsey.
Even with Boehner’s backing, polls show many Americans remain skeptical about the need for a U.S. role in Syria. And there is no guarantee that Boehner will convince enough of his fellow Republicans in Congress to approve U.S. action.
In addition to building support at home for action against Syria, the president will discuss this week in Europe. He is flying to Sweden overnight for a one-day visit, then will attend the G20 summit Thursday and Friday in St. Petersburg.
Russia's role pivotal
British Prime Minister David Cameron also is expected to urge Syria’s top ally, Russia, to work with Western allies toward a political solution to Syria’s civil war. Russia has blocked previous U.N. efforts to impose sanctions on Assad’s government.
Last week, Parliament rejected Cameron’s proposal for British participation in a military response to the suspected chemical weapons attack on August 21.
French President Francois Hollande Tuesday called on Europe to forge a united response to Syria. However, he said France would wait for the U.S. Congress to vote on Obama’s plan for a strike before taking any military action.
The flow of refugees out of Syria has risen dramatically in recent months. The United Nations refugee agency says more than 2 million people have fled the country - up from 231,000 a year ago.
'A disgraceful humanitarian calamity'
UNHCR chief Antonio Guterres said Syria has become "a disgraceful humanitarian calamity, with suffering and displacement unparalleled in recent history." He added that "the only solace is the humanity shown by the neighboring countries in welcoming and saving the lives of so many refugees."
The U.N. says many of the refugees flee with little more than the clothes on their back, and that half of them are children. It has made appeals for international aid, but said Tuesday it has received only 47 percent of the money required to meet the basic needs of the refugees.
With 4.25 million more people displaced within Syria, the conflict has forced more than a quarter of the country's population to leave their homes.
The crisis that began in March 2011 as an uprising against President Assad's rule has left more than 100,000 people dead.
Assad denies his military was responsible for the use of chemical weapons, and he has challenged the United States and France to prove their allegations. In an interview with the French newspaper Le Figaro, he warned that a military strike by those countries could start a regional war.
Russia, a long-time Syrian ally, has also questioned the credibility of U.S. evidence that the Assad government used chemical weapons on civilians.