WASHINGTON - US forces are readying to strike Syria, though the West insists its goal is not regime change but to punish President Bashar al-Assad's government for unleashing chemical warfare on civilians.
The ground for a military intervention was laid out by US Vice President Joe Biden, who for the first time said last week's attack, thought to have killed hundreds, could only have been perpetrated by Assad's forces.
But the onrushing likelihood of action within days was met with defiance in Damascus, with regime officials pledging to fight any attack with "surprise" measures, while Syrian allies Russia and Iran warned of dire consequences.
But Britain and France also moved to back the use of force in Syria, while the White House promised to provide declassified evidence this week to prove that last Wednesday's chemical attack was the work of regime forces.
The economic cost also started to be counted, as global stocks dived and world oil prices hit a six-month high.
Analysts expect to see cruise missiles launched from US and allied submarines, ships and possibly planes, firing into Syria from outside its waters and airspace.
Biden said an "essential international norm" had been violated in Syria. "There is no doubt who is responsible for this heinous use of chemical weapons in Syria - the Syrian regime," Biden said on Tuesday.
"The president believes and I believe that those who use chemical weapons against defenseless men, women and children should and must be held accountable."