Devastation in a Damascus district (Reuters)

A European Union delegate in Syria has been killed in a rocket attack in a Damascus suburb, according to reports.

Ahmad Shihadeh, a policy officer, died in the artillery fire although it is not known if the shelling was by troops loyal to President Bashar al-Assad or by rebels, said Catherine Ashton, the EU high representative for foreign affairs.

"Ahmad died while providing humanitarian help to the community of Darayya. Ahmad was known for his courage and selflessness," she said.

The southwest Damascus suburb of Darayya, where Shihadeh died, has been a hotspot of fighting between rebel forces and government troops in recent months.

Ashton called for an end to the violence "which has led to the deaths of some 100,000 innocent citizens and over one million refugees".

Foreign Secretary William Hague is to meet his Russian counterpart Sergey Lavrov in London to discuss measures to end the bloodshed.

David Cameron has hinted that Britain may break an EU arms embargo on Syria to supply rebels with weapons.

"I hope that we can persuade our European partners that if and when a further change becomes necessary, they will agree with us," Cameron said.

"But if we can't, then it's not out of the question we might have to do things in our own way. It's possible."

Under British pressure in February, the EU modified sanctions on Syria to allow the supply of armoured vehicles, non-lethal military equipment and technical aid to carefully vetted rebel groups.