President Obama is weighing a military strike against Syria that would be of limited 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, according to senior administration officials.

The timing of such an attack, which would probably last no more than two days and involve sea-launched cruise missiles — or, possibly, long-range bombers — striking military targets not directly related to Syria’s chemical weapons arsenal, would be dependent on three factors: completion of an intelligence report assessing Syrian government culpability in last week’s alleged chemical attack; ongoing consultation with allies and Congress; and determination of a justification under international law.

“We’re actively looking at the various legal angles that would inform a decision,” said an official who spoke about the presidential deliberations on the condition of anonymity. Missile-armed U.S. warships are already positioned in the Mediterranean.