Activists said troops shot dead six people in assaults on the cities of Homs and Hama, and that at least two more people were reported killed near the Turkish border.

The latest bloodshed came as the head of the International Committee of the Red Cross, Jakob Kellenberger, ended a visit to Syria, where rights groups say 10,000 people have been arrested since anti-regime protests erupted in mid-March.

The ICRC said Kellenberger met Assad before winding up his visit, a day after the organization was for the first time granted access to a Syrian detention center.

Its delegates visited Damascus central prison in Adra suburb on Sunday.

"Initially, we will have access to persons detained by the Ministry of the Interior, and we are hopeful that we will soon be able to visit all detainees," Kellenberger said in a statement.

The ICRC said Kellenberger "welcomed the progress made in terms of access to areas affected by the ongoing violence. He emphasized one of his main concerns now is to ensure that the wounded and sick are able to obtain medical care."

On the ground, "more than 30 military vehicles and security forces raided Hama this morning and heavy gunfire was heard in the city," said Omar Idlibi, spokesman of the Local Coordination Committees (LCC).

The Syrian Observatory for Human Rights said 80 people were arrested in the Al-Khalidiyeh district of Homs, while the LCC spokesman said a sniper in the Idlib region killed a man who was trying to cross the border into Turkey.