Syria has declared as unwelcome the ambassadors of several Western states, a week after governments around the world expelled its top diplomats.
The envoys of the United States, United Kingom, France and Turkey were among 17 diplomats designated "personae non gratae", the BBC reports.
President Bashar al-Assad blamed "foreign meddling" for Syria's divisions in a speech on Sunday.
The move came as activists said at least seven people had been killed in violence throughout the country on Tuesday.
Four civilians were killed overnight in a "huge military operation" in Kafrouaid, a village in the Jabal al-Zawiya area of the northern province of Idlib, the UK-based Syrian Observatory for Human Rights said.
Troops and pro-regime militiamen supported by tanks were also reported to have stormed the town of Kfar Zita in the central province of Hama, killing two rebel fighters in the port city of Latakia.
Several villages south-west of the central city of Homs earlier came under intense army artillery- and mortar-fire, leaving three people dead, according to the Local Co-ordination Committees, an activist network.