Syrian authorities battling a year-long uprising against President Bashar al-Assad have tightened restrictions on men of military age leaving the country, Syrian and Lebanese officials said on Monday.

The restrictions issued on Saturday require men between the age of 18 and 42 to get permission from military recruitment and immigration departments before travelling, the officials said.

The move came after a year of protests against Assad and increasing reports of desertions by army conscripts.

Lebanese officials at the Masnaa border crossing between Beirut and Damascus said the number of people leaving Syria had fallen by 60 percent since the regulations were announced two days ago.

Assad has used the army to crush protests against his 12-year rule. The United Nations says more than 8,000 people have been killed in the crackdown while Syrian authorities blame foreign-backed terrorists for the violence and say 3,000 soldiers and police have been killed.

(Reporting by Afif Diab; Editing by Karolina Tagaris)