BEIRUT — Syrian tanks rolled into a Mediterranean coastal town on Saturday in an escalating crackdown by President Bashar Assad, a day after clashes with anti-government protesters left at least 30 dead nationwide, activists and an eyewitness said.

Details of the troop deployment in Banias, for weeks the scene of demonstrations demanding regime change, were scarce as phone lines and other communication with the area were mostly cut off.

An eyewitness reached by The Associated Press said soldiers deployed in Banias early Saturday.

He said tanks moved into the seaside area and were stationed in at least three Sunni villages just south of Banias, adding that soldiers were carrying out house-to-house searches and arrests in al-Marqab district about a mile southeast of the town and in the villages of Bayda and Basatin further south.

He said the army is now occupying the hilltop Marqab Castle, an 11th century crusader fortress overlooking Banias.

“Banias is now surrounded from all directions, not a single person can go in or out,” said the resident, who did not wish to be identified for fear of reprisals.

He said electricity and phone lines had been cut off, and residents were charging their mobile phones on car batteries.