LONDON, AP – Two security contractors guarding a British consulate convoy in southern Iraq were killed Saturday by a roadside bomb, Britain”s Foreign Office said.

The bomb exploded on the outskirts of Basra at 9.30 a.m., killing the two contractors who worked for the British security firm Control Risks Group, the Foreign Office said.

It was not immediately clear whether the contractors were British citizens.

Britain has some 8,500 troops in Iraq, mostly based in the south of the country. The British military headquarters is based in Basra, where Britain also has a consulate general”s office with about 20 employees.

It was not immediately clear who was in the convoy and whether any injuries were sustained in the attack.

Control Risks Group, which provides security for the consulate, said it could not comment until next of kin had been informed. The company, which describes itself on its Web site as an international business risk consultancy, specializes in helping clients operate in &#34complex or hostile environments.&#34

The company employs some 500 contractors in Iraq, a spokeswoman said. Only one contractor working for the company has previously been killed in Iraq, in an attack some 15 months ago, she added.