The kidnappers of two German engineers in Iraq have threatened to kill their captives unless Berlin cuts all links with Baghdad within 72 hours, according to a video aired by AlJazeera satellite news channel.

The footage, aired overnight Wednesday, showed the hostages apparently kneeling or sitting on the floor with four hooded men standing behind them, two of whom were armed while a third read out the kidnappers' demands, though his voice was not heard.

The kidnappers, who call themselves Brigade of Ansar al-Tawheed wal Sunnah (Followers of Unity and Prophetic Tradition), asked the German government to "close its embassy in Baghdad, withdraw German firms and cease all forms of cooperation with the Iraqi government," said the presenter of the Qatar-based television.

The captors threatened to "kill the two hostages if their demands were not met within 72 hours," he added.