Updated 10:56 PM ET
PARIS European foreign ministers on Saturday endorsed a "clear and strong response" to a chemical weapons attack that strongly points to the Syrian government, but they urged the U.S. to delay possible military action until U.N. inspectors report their findings.
U.S. Secretary of State John Kerry, trying to make the Obama administration's case for a strike, thanked the European Union for a "strong statement about the need for accountability."
Kerry said he would share his counterparts' concern with U.S. officials. A senior State Department official who attended Kerry's meeting with the ministers in Lithuania 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.
Later, at a news conference in Paris with French Foreign Minister Laurent Fabius, Kerry said "this is not the time to be silent spectators to slaughter" and that "this is not the time to allow a dictator unfettered use of some of the heinous weapons on earth."
As CBS News correspondent Margaret Brennan reported, Kerry said that waiting for the U.N. is a mistake. "If we don't confront this now, I promise the people of France and Europe and Americans, we're going to see this issue grow, and it will be required that we confront it in some other place at some other time where there may be a greater miscalculation."
Even the French, who were the first to say they'd join the us in striking assad, will now wait to see whether the U.S. Congress votes to intervene
Brennan asked Kerry why it has been so difficult to get countries to join the effort, particularly if there is anyone besides France willing to take concrete action to participate in a military action.
"Yes, the answer is... there are a number of countries, in the double digits, who are prepared to take military action," said Kerry, "and I have said previously and I repeat again, we have more countries prepared to take military action than we actually could use in the kind of military action being contemplated.
President Barack Obama has asked the U.S. Congress to approve the use of force. A final vote in the U.S. Senate is expected at the end of the coming week. A U.S. House vote is likely the week of Sept. 16. CBS News chief White House correspondent Major Garrett reports that Mr. Obama will be continuing pressing his case, both the lawmakers and the public, next week, sitting down for interviews Monday with six major networks: CBS, NBC, ABC, Fox, CNN and PBS.
A statement read at the end of the ministers' meeting by the EU's foreign policy chief, Catherine Ashton, said the Aug. 21 attack was a "blatant violation of international law, a war crime and a crime against humanity."
Information from a wide variety of sources confirmed the chemical attack, according to the statement, and "seems to indicate strong evidence that the Syrian regime is responsible" as it is the only party "that possesses chemical weapons agents and the means of their delivery in a sufficient quantity."
The statement said a "clear and strong response is crucial to make clear that such crimes are unacceptable and that there can be no impunity." But at the same time, the statement said the EU backs the need to address the crisis through the U.N. process.
The EU said it hoped a preliminary report of the investigation can be released as soon as possible and welcomed French President Francois Hollande's statement Friday to wait for this report before any further action is taken. Hollande indicated that a report could be issued by the end of next week. CBS News' Garrett reports Mr. Obama hopes the report will give him further momentum as he looks to clear the most significant congressional hurdle to military action: the House of Representatives,
The U.S. blames the government of Syrian President Bashar Assad for the attack in the Damascus suburbs 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 so far only been able to confirm 502 dead.
European officials have questioned whether any military action against the Assad government can be effective.
Britain's Parliament has voted against military action. Hollande displayed sudden caution Friday, saying for the first time that he would wait for the U.N. report before deciding whether to intervene militarily.
France, which firmly backs the Syrian rebels and has strategic and historic interest in the region, had been ready to act last week but held off when President Barack Obama declared last weekend that he would seek the backing of Congress first.
Hollande's announcement appeared to catch Fabius off guard.
Earlier Friday, Fabius told EU foreign ministers in Vilnius that there was no need to wait for the U.N. report because it would simply confirm what was already known -- that the chemical weapons attack had occurred -- but would not say who was responsible.
While the diplomatic wheels turn, rebels in Syria are eaglerly awaiting action. CBS News correspondent Clarissa Ward, reporting from the Turkish side of the Syrian border, said rebel leaders she has spoken too have expressed concerned that further delays will allow Assad the opportunity to evade serious damage. Rebels are also worried about the nature of the strikes, should they happen. If they aren't strong enough to seriously erode the Assad regime's defenses, rebels and civilians could face severe retaliations.
Kerry's trip overseas will last three days, meeting with European and Arab leaders in Lithuania, France and the United Kingdom.
Military planning is already under way to define the type of armed support provided by other countries in a proposed joint U.S.-France operation, a senior State Department official traveling with Kerry told CBS News' Brennan.
While Kerry campaigns abroad,to degrade Assad's ability to launch another chemical attack.
For a president not known for investing heavily in consultations with Capitol Hill, the coming days represent one of the most intense periods of congressional outreach in President Obama's administration. Mr. Obama seeks to salvage a policy whose fate he's placed in lawmakers' hands, planning for himself and for aides a flurry of speeches, phone calls, briefings and personal visits to Democrats and Republicans alike.
The lobbying campaign culminates Tuesday, the evening before a key vote is expected in the Senate, when Obama will address the nation from the White House to make his case that America's military must once again raise arms to protect a value he says the world simply cannot afford to place in jeopardy.
In a series of hearings this week, three of the president's top national security advisers explained that unlike the U.S.-led invasion of Iraq, this narrowly defined action would not commit the U.S. to a war nor commits American troops. Instead, this "hit and run" action is meant to send a message to Assad and to degrade his ability to use chemical weapons. No outside power has taken action to halt neither the Assad regime's actions nor the increasingly brutal war that has killed more than 100,000 people since 2011.
The senior State Department official, who is very familiar with the Syrian opposition battling Assad on the ground, argued that a failure to act by the U.S. would further destabilize the region by driving up the flow of refugees. More than two million have fled into surrounding countries since the war began. Echoing Kerry's claims that the cost of inaction outweighs the risks, the official said a failure to act would likely boost support for al Qaeda-linked extremist groups, who are providing well-armed and trained fighters to battle Assad. Those extremists have begun to control territory and to target U.S.-backed moderate rebels in yet another front of the civil war.
The U.S. effort to cultivate a strong moderate rebel force has been limited in scope and success. While the Obama administration acknowledges that the strikes are not meant to end the "grinding war of attrition" that is likely to continue long after any strikes, the U.S. believes that the Assad regime is gradually losing control of Syria.
A senior official told reporters traveling with Kerry, that the State Department is beginning to help the moderate Syrian opposition establish "law and order" in areas that the Assad regime no longer controls. The U.S. will expand a program that provides training and communications equipment to a local police force in Aleppo. This is part of a campaign to help the moderate opposition gradually win support from the local communities.
On Mideast peace negotiations, Kerry urged his EU counterparts to consider delaying putting in place a funding ban on Israeli institutions operating in occupied territories.
Ashton said the EU would send a team to Israel on Monday to make sure the implementation of the ban is done "very sensitively."
"We, of course, want to continue to have a strong relationship with Israel," she said.
The EU's decision on the ban, announced in July, marked a new international show of displeasure with Israeli settlements built on lands captured in the 1967 Mideast war.
The Palestinians claim some of those territories -- the West Bank, Gaza Strip and east Jerusalem -- for their hoped-for state.
The EU ban applies to grants, prizes and financial instruments and that the new funding guidelines go into effect in 2014. The EU issues dozens of grants, totaling millions of euros, to Israeli universities, companies and researchers every year.