WASHINGTON, Aug. 27 (Xinhua) -- U.S. President Barack Obama spoke to Canadian Prime Minister Stephen Harper on Tuesday in his ongoing consultations over how to respond to the purported use of chemical weapons in the Syrian conflict.
In their phone conversation, the two leaders expressed their " grave concern" about the episode in Syria's 29-months strife between the government and opposition forces.
"The United States and Canada strongly oppose the use of chemical weapons," the White House said in a readout of the talks, adding the two leaders pledged continued consultations over " potential responses."
Obama had spoken to leaders of Britain, France and Australia in the past few days, as he is considering limited military strikes on military targets not directly related to Syria's chemical weapons arsenal.
The Washington Post said Tuesday that the forthcoming attack would probably last no more than two days and involve sea-launched cruise missiles or possibly long-range bombers. The U.S. Navy now has four warships armed with cruise missiles in the Mediterranean.
U.S. Defense Secretary Chuck Hagel told the BBC on Tuesday that the U.S. military stands ready to strike Syria at once if Obama gives the order.
U.S. Secretary of State John Kerry on Monday called the use of chemical weapons in Syria "a moral obscenity," saying it is " inexcusable" and "undeniable." He said Obama "believes there must be accountability for those who would use the world's most heinous weapons against the world's most vulnerable people," and the president will make an "informed" decision on how to respond.
The Syrian government and opposition have traded blame for the chemical attacks in the suburbs of Damascus, capital of Syria, on Aug. 21, in which as many as 1,300 people were reportedly killed.
While UN investigators were on the scene collecting evidence, Washington and its allies have blamed the Syrian government for the attack.
Russian Foreign Minister Sergei Lavrov on Monday warned the Western powers against military strikes on Syria, calling the move "a very dangerous and slippery path."
Some analysts warned that military strikes on Syria could trigger a wave of terrorist attacks against the United States and Israel.