Syrian forces killed five civilians and injured scores in a raid on protesters in the town of Mayadeen as Arab ministers prepared to meet in Cairo on Saturday to discuss President Bashar Assad's bloody crackdown.

"The Arab League will hold an urgent meeting on Saturday on the latest events in Syria," Shaikh Hamad Bin Jasem Bin Jabr AlThani, Qatar's Prime Minister and Foreign Minister, said.

Dozens were arrested in Mayadeen and neighbouring cities and in the centre of the Deir Al Zor province, in the second military action in the region this month. A force of 20-30 tanks and other armoured vehicles entered neighbourhoods in Mayadeen and the nearby village of Alburhama in the east.

"They are mainly hit-and-run raids. The military is trying to avoid reprisals from the population, which is heavily armed. So they go quickly to arrest people, sabotaging houses of wanted activists they cannot find," a local activist told Reuters by telephone.

Meanwhile, the EU named the elite Al Quds unit of Iran's Revolutionary Guards along with five Syrian generals, and the entire military intelligence network in Syria, on a fourth list of sanctions against Damascus.

The inclusion of the Iranian unit in the sanctions underscores previous reports Iran and its Lebanon-based proxy Hizbullah have been active participants in the Assad's crackdown that has, to date, left at least 2,200 civilians dead.