Reuters Cameraman Salim Uraibi said the men identified themselves as Andrei Meshcheryakov and Alexander Gordiyenko. They were kidnapped on 10 May in an ambush in which one of their colleagues was killed. 

They were handed over at the home of a local shaikh who apparently helped negotiate the release of the men, both employees of Russian energy services company Interenergoservis. 

The company had already pulled scores of its staff out of Iraq last month after several other employees were briefly seized. 

Aljazeera on Sunday aired a tape showing the hostages being held by a group calling itself "The Army of the Victorious Sect". In the tape, the group called for an end to the "criminal project (Iraq's occupation) before it was too late."

Dozens of hostages have been abducted by fighters in Iraq since the start of April. 

Most have been released, but an Italian hostage was killed last month and earlier this month American Nicholas Berg was beheaded by his captors, who posted a video of the decapitation on the internet. 

At least three Italians remain in captivity, but it is unclear how many other outstanding hostages there are.