U.S. President Barack Obama is weighing a limited military strike against Syria in response to its purported use of chemical weapons in internal conflict, The Washington Post said on Tuesday.

Syrian soldiers are seen at the battlefront of Jobar, near the capital of Damascus, on Aug. 24, 2013. Some Syrian soldiers on Saturday suffered suffocation after rebel militants released chemical substance around their hideouts near Damascus, the state-TV reported. [Bassem Tellawi/Xinhua]

The military operation will be limited both in scope and duration, "designed to serve as punishment for Syria's use of chemical weapons and as a deterrent, while keeping the United States out of deeper involvement in that country's civil war," the paper reported, quoting senior administration officials.

It said the president will time his decision on three factors -- completion of an intelligence assessment regarding the Syrian government's culpability in the alleged chemical attack on Aug. 21, ongoing consultations with allies and Congress and determination of a justification under international law.

U.S. Secretary of State John Kerry said on Monday that the assessment will come out in the days ahead, while Obama has called leaders of Britain, France and Australia in the past few days to discuss possible responses to the latest development in Syria. Both Kerry and Defense Secretary Chuck Hagel have ongoing consultations with their foreign counterparts.

In his Monday statement, Kerry 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 that the president will make an " informed" decision on how to respond.

Obama set a "red line" a year ago over the use of chemical weapons in Syria's conflict, which has dragged on for 29 months and claimed more than 100,000 lives.

The newspaper said the forthcoming attack would probably last no more than two days and involve sea-launched cruise missiles or possibly long-range bombers, and it will focus on military targets not directly related to Syria's chemical weapons arsenal.

Hagel told BBC on Tuesday that the U.S. military stands ready to strike Syria at once if Obama gives the order.

Britain, France and Turkey have said that they would support action if the use of chemical weapons was confirmed.

"What we are talking about here is a potential response ... to this specific violation of international norms," White House spokesman Jay Carney told reporters on Monday. "While it is part of this ongoing Syrian conflict in which we have an interest and in which we have a clearly stated position, it is distinct in that regard."

The Syrian government and opposition have traded blame for the chemical attacks in the suburbs of Damascus, capital of Syria, in which as many as 1,300 people were reportedly killed. UN investigators were on the scene collecting evidence.

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 on Monday that military strikes on Syria could trigger a wave of terrorist attacks against the United States and Israel.