Syrian troops on alert amid fear of US strike after 'chemical attack'

Syrian government forces and their allies are on alert and taking precautionary measures at military bases and posts in government-held areas across the country amid fears of a US strike in the aftermath of an apparent chemical weapons attack, war monitors said.

The measures came as a senior Iranian official visiting Damascus warned that Israel's air strike on a Syrian air base on Monday that killed several Iranians "will not remain unanswered".