President Barack Obama says he has decided the United States should take military action against Syria for that government's alleged use of chemical weapons, but he says he will seek authorization from Congress for any use of force.
In a Saturday address to the nation, Mr. Obama said that while he has the authority to act on his own, he believes it is important for the country to have a debate on the issue.
The president said the U.S. cannot and will not turn a 'blind eye" to what happened in Damascus.
He said the Syrian government's alleged attack has implications beyond chemical warfare.
"If we won't enforce accountability in the face of this heinous act, what does it say about our resolve to stand up to others who flout fundamental international rules? To governments who choose to build nuclear arms? To terrorists who would spread biological weapons? To armies who carry out genocide?"
Mr. Obama said any U.S. intervention in Syria would not be open-ended and would not include U.S. ground troops.
As he spoke outdoors in the White House Rose Garden, protesters outside the grounds chanted and waved signs to voice opposition to U.S. military intervention in Syria.
Meanwhile, a flurry of diplomatic activity is under way on Syria's crisis.
The White House says senior national security officials are holding conference calls with Senate leaders on Saturday. On Sunday, the White House plans to hold a classified briefing on Syria for the House of Representatives.
Republican leaders in the House say they are glad Mr. Obama is seeking authorization for any military action. In a Saturday statement, they said that under the U.S. constitution, "the responsibility to declare war lies with Congress."
A U.N. chemical weapons inspection team has wrapped up its work and left Syria.
A spokesman for Secretary-General Ban Ki-moon said the U.N. chief will be briefed again on Sunday by the head of the team. The spokesman declined to say when the team will present its full report.
He said the team collected samples that will be analyzed in laboratories as well as witness statements and interviews with doctors and survivors.
Mr. Obama said he has confidence in a report from the U.S. intelligence community that indicated the Syrian government was responsible for the attack, and he does not feel compelled to await the outcome of the U.N. probe.
"I am comfortable going forward without the approval of a United Nations Security Council that, so far, has been completely paralyzed and unwilling to hold Assad accountable."
The Syrian government has denied any role in chemical weapons attacks.
Also Saturday, Russian President Vladimir Putin said it would be "utter nonsense" for the Syrian government to use chemical weapons when it is winning the war against "rebels."
In a statement, Mr. Putin urged the U.S. to allow the U.N. chemical weapons team to present its findings.
"As for the position of our American colleagues and friends who state that the government forces have used weapons of mass destruction, in this case used chemical weapons, and say that they have evidence - let them present them to the U.N. inspectors and the U.N. Security Council.''
On Friday, U.S. Secretary of State John Kerry said evidence presented in a declassified version of a U.S. intelligence report shows more than 1,400 Syrians were killed in the attack, including at least 426 children.