The EU nations, most of which have been skeptical of a quick retaliatory strike against the regime, underscored "the need to move forward with addressing the Syrian crisis through the U.N. process." The ministers said they hope a "preliminary report of this first (U.N.) investigation can be released as soon as possible."
Kerry welcomed the stand of the 28 EU nations, calling it "a strong statement" backing all "the efforts to hold the Assad regime accountable for what it has done."
The German newspaper Frankfurter Allgemeine Sonntagszeitung reported Saturday that the U.N. chemical weapons inspectors could submit initial findings from their tests of samples collected in Syria by the end of next week. The respected weekly said the interim report to U.N. chief Ban Ki-moon will likely contain details on the gas, ammunition and delivery systems used in the attack that killed hundreds of people in a suburb of Damascus.
Instrumental in bringing the EU together around a common viewpoint was the decision on Friday by French President Francois Hollande to wait for the U.N. report before deciding to intervene militarily, even though France had said the report would only show a chemical attack had taken place, not apportion blame.
The EU ministers welcomed "President Hollande's statement to wait for this report before any further action."
German Foreign Minister Guido Westerwelle said the U.S. should follow France's example.
"We jointly welcomed the fact that France has decided to wait for the presentation of the United Nations report," Westerwelle told reporters. "We have also made clear our expectation toward our American partners that one should follow the example of France before capitals decide on taking further measures."
The EU ministers also stressed that perpetrators for such chemical attacks should face possible prosecution by the International Criminal Court in The Hague.
Germany joined in on blaming the attack on the Syrian government. It had been the only European member of the Group of 20 not to co-sign a joint statement issued Friday at the end of the group's meeting in St. Petersburg, Russia, blaming the regime.
That G-20 statement calls for a strong international response against Assad's regime but stops short of explicitly calling for military action against the Syrian government. German Foreign Minister Guido Westerwelle said Saturday in Vilnius that his country wanted to wait for EU foreign ministers to agree on a common position before backing the statement.
Kerry said Saturday he would share his counterparts' concern with Obama administration officials. A senior U.S. State Department official who attended Kerry's meeting with the ministers said Kerry made clear that the U.S. has not made any decision to wait. The official spoke on condition of anonymity to disclose details about the private meeting.
"My impression is that the American side understood our expectations and that they will consider this in their own decision-making process," Westerwelle said.
The U.S. blames Assad's regime for the chemical attack and, citing intelligence reports, says sarin gas was used. The U.S. says 1,429 people died, including 426 children.
The Britain-based Syrian Observatory for Human Rights, which collects information from a network of anti-regime activists, says it has only been able to confirm 502 dead.
Associated Press Writers Deb Riechmann in Vilnius and Frank Jordans in Berlin contributed to this report.