UN-Arab League envoy Lakhdar Brahimi told the UN Security Council on Monday that the Syrian civil war is worsening and the country faces a growing food crisis, envoys at a closed meeting said.

Brahimi told the 15-nation council that the Syrian government estimates there are 5,000 foreign fighters in the country and is increasingly portraying the conflict as a "foreign conspiracy," envoys at the meeting told AFP.

The former Algerian foreign minister, who reported on his recent talks with President Bashar al-Assad in Damascus, painted an increasingly grim picture of the 18-month-old conflict in which activists say more than 29,000 people have died.

Brahimi told the council that the torture of detainees has become "routine" and that people were now afraid to go to hospitals which were in the hands of government forces.

The envoy estimated that 1.5 million people have now fled their homes and said Syria faces growing food shortages because harvests have been slashed by the fighting between government forces and opposition rebels.