“The Syrian authorities have granted the I.C.R.C. access to a place of detention for the first time,” the group’s president, Jakob Kellenberger, said in a statement issued at the end of a two-day visit to Damascus. “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.”

Mr. Kellenberger met with Mr. Assad and the foreign minister, Walid al-Moallem, during his visit. The group’s findings were not made public, and Syrian authorities have not revealed the number of detainees, contending that all arrests were legal and that torture did not take place.

At the same time as the visit, Syrian troops raided several cities and towns across the country in search of activists and protesters who were involved in planning the uprising, human rights campaigners and residents said. They said that troops also raided homes and combed areas in northern Syria near the Turkish border and in central Syria looking for the attorney general, Adnan Bakkour, whose resignation greatly embarrassed the government.

In a video posted online this week, Mr. Bakkour said security forces had attacked his convoy last Friday in the northern province of Idlib, arguing that four people were killed in the operation and several others wounded. He said he, too, was wounded from shrapnel, but that protest leaders had helped him escape.

Omar Idlibi, a spokesman for the Local Coordination Committees, a grass-roots group that organizes and tracks the uprising, said that Mr. Bakkour had left the country and is currently in a safe place. There were reports by other activists saying that Mr. Bakkour had made it to Turkey or Cyprus. Human rights campaigners believe that Mr. Bakkour has enough evidence to take action against Mr. Assad and his government in the International Criminal Court.