Washington: The Obama administration has concluded Syrian President Bashar al-Assad's regime probably used chemical weaponry against civilians, calling an agreement to let United Nations inspectors review the area not credible.
Syria and the UN agreed to the inspection of the Ghouta area outside Damascus starting on Monday, a UN spokesman said. The agreement five days after the purported attack is too late because constant shelling of the area could have corrupted or destroyed evidence, according to a senior US administration official.
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Syria releases video of chemical agents
US President Barack Obama meets with his security team to discuss options on Syria after reports of alleged chemical weapons use.
Pressure is building on President Barack Obama to respond, with Senators John McCain and Lindsey Graham, Republicans on the Senate Armed Services Committee, calling today for a limited military response by the US and its allies. The US, the UK and France are discussing options.
US intelligence officials and international partners have concluded that chemicals were used, based on the reported number of victims, reported symptoms of those who were killed or injured in the August 21 attacks, witness accounts and other facts gathered, according to the US statement.
"There is very little doubt at this point that a chemical weapon was used by the Syrian regime against civilians in this incident," according to the official's statement. The official's statement was released on condition of anonymity because the person wasn't authorised to speak publicly.
Some opposition groups say 1300 people were killed in the attack in the Damascus suburb.
The Syrian government, which has denied the claim, will cooperate with the UN's review, according to the state-run Sana news agency.
According to the UN statement, the Syrian government agreed to cease hostilities in the area so the inspectors can do their job efficiently and thoroughly.
The passing of time since the attack will make it more difficult to identify what occurred and which chemical agents might have been used, according to Rolf Halden, a professor at Arizona State University.
"If undertaken too late -- days after alleged attack -- a chemical monitoring effort may be imperfect and prone to yield ambiguous or inconclusive results," Mr Halden, who is part of the university's program on security and defence systems, said.
French President Francois Hollande conferred with Mr Obama on Sunday about the situation in Syria. The US and UK are now examining "all the options" for dealing with Syria, British Prime Minister David Cameron's office said in a statement after he spoke by phone with Obama.
Israeli Prime Minister Benjamin Netanyahu said in a statement that Iran and Hezbollah are playing an active role in Syria.
Top US intelligence and national security officials are still assessing the facts before Obama decides how to respond, according to the statement. The US president said a year ago that the use of chemical weapons by the Assad regime would cross a US "red line."
US Defence Secretary Chuck Hagel said the US military is ready to act if Obama orders a strike on Syria. "The Defence Department has a responsibility to provide the president with options for all contingencies," he told reporters en route to Kuala Lumpur, at the beginning of a week-long visit to the region.
Preparations include the repositioning of personnel and assets including ships, a senior US defence official told reporters, speaking on condition of anonymity to discuss internal planning.
Mr Obama met with his national security team on Sunday to discuss the reports. US intelligence officials along with international partners are continuing to gather evidence about what happened, according to a White House statement issued after the meeting.
The president received "a detailed review of a range of potential options he had requested be prepared for the United States and the international community to respond to the use of chemical weapons," according to the White House statement.
The US now has four destroyers equipped with Tomahawk cruise missiles in the Mediterranean Sea, compared with three that have been there for months, according to a US official familiar with the forces there. None of the ships -- the USS Gravely, the USS Barry, the USS Mahan and the USS Ramage -- has been assigned a mission, the official said.
The US response should be conducted in a "surgical and proportional way," Senator Bob Corker, the top Republican on the Senate Foreign Relations Committee, said on "Fox News Sunday." The US should also act in a way that allows opposition forces in Syria to take the lead, said Senator Corker of Tennessee.
"We have to act rather quickly," Representative Eliot Engel, a New York Democrat and ranking member on the House Foreign Affairs Committee, said on the Fox program.