But with three attacks on diplomats in four days, at least some Arab and Muslim governments were raising questions about security as a condition for upgrading ties to the new Iraqi government, as the United States wants.

The threat to kill Ihab al-Sherif, seized by gunmen in western Baghdad on Saturday, marks a dramatic escalation in a campaign to isolate Iraq diplomatically in the Arab and Muslim worlds. On Tuesday, gunmen fired on senior envoys from Bahrain and Pakistan in apparent kidnap attempts.

''Terrorism is trying to strike not only against Iraqis,'' Iraqi Prime Minister Ibrahim al-Jaafari told reporters after meeting with Sen. Carl Levin, ranking Democrat on the Senate Foreign Relations Committee and a critic of U.S. policy in Iraq.

''We hope that all countries of the world will stand by us, strengthen the democratic work and carry out political functions, keeping in mind the security regulations,'' al-Jaafari said.

The threat on al-Sherif's life came in a statement on a Web site linked to al-Qaida.

The statement condemned Egypt for allying itself with ''Jews and Christians'' - in other words, it linked the kidnapping to Egypt's announcement last month that it would be the first Arab government to upgrade its mission here to a full embassy headed by an ambassador. Egyptian officials say no ambassador has been designated although al-Sherif was posted here a few weeks before the announcement.

More than a dozen Arab nations have diplomatic missions in Baghdad, but none has a full ambassador - in part because of security fears and in part because governments are hesitant to take a step that could be seen as condoning the U.S. military presence in Iraq.

Jordan's deputy prime minister, Marwan Muasher, said his country was ''determined'' to send an ambassador ''but we are awaiting measures to be put in place to ensure his safety in Iraq.''

Pakistan's Ambassador Mohammed Younis Khan flew to Jordan a day after his convoy was fired on in west Baghdad. Bahraini envoy Hassan Malallah al-Ansari, slightly wounded in a separate shooting, was expected to depart within a few days.

In the Web statement, the kidnappers said al-Qaida in Iraq's religious court had decided to hand over al-Sherif, 51, to its fighters ''to carry out the punishment of apostasy against him.''