Islamic militants have threatened to kill an Italian journalist abducted in Iraq by Monday unless Italy agrees to withdraw its troops, according to a statement on the Internet.

The statement, which appeared Saturday on an Internet bulletin board that serves as a clearinghouse for messages from extremist groups, said Giuliana Sgrena (search), 56, would be subjected to the "rule of God," a phrase that usually means punishment by death in the lexicon of Islamic militant groups.

There was no way to verify the authenticity of the statement.

"We in the Jihad organization in the land of the two rivers announce that the rule of God will be carried out on the Italian hostage after 48 hours if the Italian government headed by (Italian Prime Minister Silvio) Berlusconi the criminal does not announce Italy's withdrawal from Iraq."

Sgrena, a veteran reporter for the left-wing daily Il Manifesto (search), was kidnapped Friday by gunmen who blocked her car outside Baghdad University.

The new Web message was signed by the Jihad Organization. It wasn't clear whether the group was the same as one that posted an Internet statement hours after the abduction on Friday.

In that message, a group calling itself the Islamic Jihad Organization (search) claimed to have kidnapped the woman and gave Italy 72 hours to withdraw its troops. But it made no threats to kill her or say what would happen if its demands were not met.

The Italian Foreign Ministry has said it was skeptical of that Internet claim.

Neither statement included a picture of the woman or other evidence to support the claims.

Italy has around 3,000 troops in Iraq, the coalition's third largest contingent after those of the United States and Britain.