Syrian activists say at least 17 opposition fighters have been killed during clashes with government troops near the Lebanese border.

The UK-based Syrian Observatory for Human Rights , which opposes Syrian President Bashar al-Assad, said on Friday that the opposition fighters died overnight on Thursday near Yabroud.

It also said that government aircraft carried out six airstrikes on rebel positions on the outskirts of the town on Friday.

There were no immediate reports of civilian casualties from the attacks. The group relies on reports from activists and doctors on the ground.

Yabroud is the last rebel stronghold in Syria's mountainous Qalamoun region that stretches to the border with Lebanon. The Syrian army has been advancing on the town, trying to recapture it and regain vital supply routes in western Syria.