Syrians mounted their largest demonstrations yet as antiregime protests moved past their fourth month on Friday, after the opposition earlier in the week rejected talks with the government and the regime retaliated with force.

About a million people marched in the cities of Hama and Deir el-Zour alone on Friday, according to the Syrian Observatory for Human Rights, a rights group.

Thousands demonstrated in Damascus, marking the largest protests in the capital, activists said. A witness said at least 14 people were killed in one district as special forces wielding machine guns opened fire on the crowd.

"I've never seen this much blood in Damascus," the person said by telephone as he escaped gunfire in the capital's Qaboun district.

Authorities had previously contained large protests in the capital and Aleppo, Syria's second-largest city, both strongholds of President Bashar al-Assad.