A double suicide attack targeted a convoy of Indian roadworkers on Saturday in southwestern Afghanistan, killing two engineers and injuring several people, a local governor said.

The bombers struck simultaneously and authorities said a third suspected attacker was captured with an explosive-filled jacket.

There was a suicide attack carried out by two suicide bombers against Indian roadworkers who were working on a bridge. Two Indian engineers were killed. Several other people including three Indians were injured.

A Taliban purported spokesman, Yousuf Ahmadi, claimed responsibility but gave a different version about the attack.

He said at first two mines planted by insurgents were detonated, after which a bomber blew himself up.

"It was carried out by our mujahedeen (holy warriors)," rebel spokesman, Ahmadi told AFP by phone.

"First they detonated two mines that we had buried in the area. After police and the Indians gathered there one of our devoted members carried out a suicide bombing," he added.

The bombing in Nimroz province follows a suicide car bombing in the southern province of Kandahar which killed eight civilians on Thursday.

In New Delhi, Defence Minister A.K. Antony expressed shock at the bombing but said the Indian military-backed road construction project would continue.

"It is a rude shock as this tragedy has happened when the road construction was in its final phase," the Press Trust of India quoted Antony as saying.

Antony said he had conveyed India's worries about the security of its road workers to Afghanistan's Defence Minister Abdul Rahim Wardak during his recent visit to India.

Despite the attack, India will "continue to help the rehabilitation process in that country by ensuring security of Indians engaged in projects," he said, adding that the bodies of the slain workers would be flown back shortly.