Syrian President Bashar al-Assad has replaced the governor of a troubled eastern province as army units continue their brutal nationwide crackdown on anti-government protesters.

Mr. Assad on Sunday appointed former Damascus-based police brigadier general Samir al-Sheik to run the oil-rich province of Deir al-Zor, two days after the region saw the biggest protests yet demanding an end to his authoritarian rule.

Sheik replaces Hussein Arnos, a civilian, who was transferred to the small province of Qunaitera west of Damascus.

Activists say a half-million people took to the streets Friday across Deir al-Zor, a tribal area that borders Iraq's Sunni heartland. Last week, the army surrounded the town of Albu Kamal, on the easternmost edge of the province, after 30 soldiers defected following the killing of four protesters.

The French news agency quoted activists as saying the Syrian army took control of several areas in the city of Homs on Sunday, deploying heavily in the Duar al-Fakhura and al-Nazihin neighborhoods. Homs has been a focal point of the protest movement and the government's crackdown on dissent.

Authorities also swept through Damascus Saturday, detaining scores of people. AFP reported that government troops set up roadblocks on routes into the capital's Qabun district, and deployed in front of mosques with automatic rifles.

Rights groups say Syrian forces have killed at least 1,600 civilians during the government's crackdown on dissent, while the government has blamed much of the violence on terrorists and Islamists who it says have killed hundreds of security personnel.

It is hard to verify accounts of the unrest in Syria because its government has barred most foreign media from reporting and traveling freely in the country.