PARIS  The protests sweeping the Middle East reached Libya on Wednesday, with demonstrations against its leader, Col. Muammar el-Qaddafi, reported in several cities.

In Benghazi, Libya’s second-largest city, a crowd armed with gasoline bombs and rocks protested outside a government office to demand the release of a human rights advocate, Reuters and other news agencies reported. The demonstrators, estimated at several hundred to several thousand, marched to the city’s central square, where they clashed with riot police officers.

In the city of Zentan, hundreds marched through the streets and set fire to security headquarters and a police station, according to The Associated Press. The A.P. also said that anti-Qaddafi demonstrations broke out in Al Beyda, east of Benghazi. In both cities, the protests were also spurred by the arrest of human rights advocates, news agencies reported.

Protesters using social networking sites like Twitter and Facebook are calling for nationwide demonstrations on Thursday to demand Colonel Qaddafi’s ouster.