U.S. Secretary of State John Kerry says international support is growing for holding the Syrian government responsible for its alleged chemical weapons attack.
"This is growing, not receding, in terms of the global sense of outrage of what's happened."
He commented during a Saturday news conference, in Paris, with French Foreign Minister Laurent Fabius.
Earlier in the day, Kerry met with European foreign ministers in Lithuania in a bid to strengthen support, as the U.S. considers a possible military strike against Syria.
After the meeting, EU foreign policy chief Catherine Ashton read a statement for the group that called for a "clear and strong response" to the attack in Syria but stopped short of specifying military action.
Ashton also said the EU wants Syria's crisis to be addressed by the United Nations. She said any further action against Damascus should be delayed until a U.N. chemical weapons team presents its findings.
In Paris, Kerry said the European leaders had made a "powerful statement" even though some countries still did not believe in military action.
He also said President Barack Obama had not made a decision on waiting on the report from the U.N. team.
Meanwhile, Mr. Obama, in his weekly radio address, said failing to respond to what he called Syria's "outrageous attack" would increase a risk of further chemical weapons attacks.
In the address, broadcast on Saturday, he also said the Syrian government's alleged use of chemical weapons was a "direct attack on human dignity" and a threat to national security.
The president's address on Syria came a day after he wrapped up a visit to Russia for the G20 economic summit.
During the trip, Mr. Obama held bilateral meetings on Syria with leaders of the world's major economies. He received support from the leaders of France, Turkey and other nations, but Russian President Vladimir Putin remained adamantly opposed to any attack on the government of Syrian President Bashar al-Assad.
Mr. Obama takes his case for targeted military strikes on Damascus directly to the American people in a televised speech Tuesday.
The U.S. Congress is expected to vote on possible U.S. action against Syria in coming weeks. A key Senate panel voted on Wednesday in favor of action.
U.S. officials say they have evidence that more than 1,400 people were killed by poison gas in an attack on August 21 in areas on the fringe of Damascus populated by supporters of the opposition.
In Syria Saturday, opposition activists say at least 16 people were killed in heavy shelling near Damascus.