Captors seize Bulgarian hostages

The gunmen have threatened to execute the hostages

An Islamic militant group in Iraq has threatened to kill two Bulgarian hostages - the latest to be captured.

A videotape broadcast by al-Jazeera television shows two men with their hands tied, flanked by three gunmen.

The message said the men would be executed if Iraqi prisoners were not freed within 24 hours.

The al-Tawhid and Jihad militants - led by top al-Qaeda suspect Abu Musab al-Zarqawi - have already beheaded a US and a South Korean hostage.

Bulgaria has a 485-member battalion in Iraq, which serves alongside Ukrainian troops under Polish command.

HOSTAGES KILLED 14 April: Fabrizio Quattrocchi, 36, Italian security guard is shot dead 11 May: Nick Berg, 26, US businessman is beheaded 22 June: Kim Sun-il, 33, South Korean translator is beheaded 29 June: Keith Maupin, 20, US soldier is reportedly killed (not confirmed)

The latest kidnap came hours after a Lebanese-born US marine who was allegedly kidnapped in Iraq, turned up in the US embassy in Beirut.

Cpl Wassef Ali Hassoun's disappearance has been mired in confusion - last weekend he was reported to have been beheaded by his Islamist captors.

Iraq captors holding a Filipino hostage have threatened to kill him unless Manila withdraws its troops from Iraq within 72 hours.

It is not known how many hostages Iraqi militants hold in Iraq.