Baghdad, Jan. 18 (Reuters): Insurgents in Iraq threatened to kill eight Chinese hostages today as Baghdad officials said they would close land borders and restrict traffic across the country in a bid to thwart attacks during next week?s election.

A bomb attack on a Shia political party office refreshed fears of sectarian violence by the mostly Sunni insurgents but the swift release of the kidnapped archbishop of Mosul was greeted with relief by the beleaguered Iraqi Christian minority.

Beijing, no ally of the US and a critic of its invasion of Iraq, was drawn into the anarchy that has followed when insurgents released a video of eight Chinese men and threatened to kill them in 48 hours if China failed to explain why they were apparently building facilities for the Americans.

?The position of the Chinese government towards our cause was clear ? not taking part in invasion forces and their aggression against our country,? said a voice on the tape, which showed masked gunmen keeping the men against a wall.

?We call on the Chinese government to clarify its position on them and other Chinese. We will kill them 48 hours after their pictures are televised unless that is done.?

The militants identified themselves as from the Nuamaan Brigade of the Islamic Resistance.

The Chinese state news agency Xinhua said Chinese diplomats in Iraq were working to free the construction workers from Fujian province, who had gone missing last week. It gave no details of the men?s work.

Twelve days before an election Washington hopes can install a legitimate government, two years after the overthrow of Saddam Hussein, officials in Baghdad announced several measures aimed at thwarting insurgents bent on wrecking the January 30 poll.

A statement from Iraq?s election commission said land frontier posts would be closed and tight restrictions declared on all vehicle traffic from January 29-31, a set of extraordinary measures to prevent a bloodbath on election day.

Police said a suicide car bomber today killed one person and wounded seven outside a Baghdad office of the Supreme Council for the Islamic Revolution in Iraq.