BEIRUT, Lebanon −The United Nations human rights office said in a report issued on Thursday that at least 2,900 people have been killed in Syria since pro-democracy protests began there in mid-March.

The announcement came as activists in Syria said that at least 12 people were killed during clashes between armed men loyal to the government of President Bashar al-Assad and soldiers who deserted their ranks, in the northern province of Idlib, near the Turkish border.

There have been signs in recent weeks that the Syria uprising, which started as a peaceful movement inspired by events in Egypt and Tunisia that toppled governments there, is increasingly becoming an armed struggle, as protesters resist the government's harsh crackdown.

The United Nations’ previous total of deaths in the Syria uprising was 2,700.

President Assad's government, which generally denies reports of human rights abuses, has characterized the uprising as a foreign-backed insurrection led by thugs and has said it has no choice but to restore law and order.