Canadians travelling or living in Syria should leave the country immediately and trips to the country should be avoided due to the deteriorating security situation, Foreign Affairs warns.

"There has been extensive use of force by the security forces and military in suppressing demonstrations across the country," a release issued Friday says. "Many casualties and fatalities have been reported and protests and violent repression are likely to continue."

The UN High Commissioner for Human Rights Navi Pillay, meanwhile, said Friday more than 3,000 people have been killed since the uprising against President Bashar Assad began in March.

Security operations by government forces can involve the lockdown of entire cities, including roadblocks and checkpoints, and may last for weeks, the release says. Communications services could also be disrupted, it warned.

Anyone in the country should avoid political gatherings or crowds as they may turn violent without warning, the release says.

Canadians in the country should also contact the Canadian Embassy in the capital of Damascus and make sure travel documents are up to date.