U.S. forces seized hundreds of mortar rounds and rockets in a Sunni neighborhood of Baghdad and detained two suspected terrorists Friday. Jordan became the first Arab country to send a fully accredited ambassador to Iraq.

Authorities ordered all vehicles off the roads starting Friday night for two days in more than a dozen Baghdad neighborhoods to forestall violence during a mass rally commemorating the death of an 8th-century Shiite saint.

Jordan's Ambassador Ahmed al-Lozi presented his credentials to Iraqi President Jalal Talabani on Thursday, said a statement by the president's office.

Al-Lozi arrived Tuesday with Jordanian Prime Minister Marouf al-Bakhit, who was on a three-day visit, and stayed behind to take up his duties, Talabani's aide, Hiwa Othman, told The Associated Press.

CountryWatch: Iraq

Al-Lozi is the first fully accredited Arab ambassador in Iraq. Egypt sent an ambassador, Ihab al-Sherif, last year but he was kidnapped and killed in July 2005 before he could present his credentials.

Despite U.S. pressure, Arab countries have dragged their feet on sending ambassadors to Iraq because of the violence raging in the country since the March 2003 ouster of Saddam Hussein in the U.S.-led invasion.

The violence has seen a sharp spike in recent months — about 3,500 Iraqis were killed in July in sectarian or political violence nationwide, the highest monthly toll for civilians since the war started in March 2003.

A U.S. military statement said soldiers from the 172nd Stryker Brigade Combat Team discovered a cache of weapons in a warehouse while conducting searches Friday in Shula and Ghazaliyah, two hotspot areas of Baghdad where support for Sunni insurgents runs deep, a U.S. military statement said.

The Stryker Brigade is part of the 12,000 U.S. and Iraqi soldiers rushed to Baghdad this month to control the rising tide of insurgency by Saddam loyalists and sectarian violence between Sunnis and Shiites.

The tit-for-tat attacks by Shiites and Sunnis since the Feb. 22 bombing of a Shiite mosque has raised fears of an all-out civil war, and diverted resources needed to fight the insurgency.

The U.S. statement said the seized weapons included 583 rounds of mortars, 104 rocket propelled grenades, 249 rockets, machine guns, automatic rifles, ammunition and bomb making equipment.

Two suspected terrorists were detained for questioning, it said.

A separate Iraqi statement said soldiers raided the Al-Sediq Sunni mosque in Ghazaliyah on a tip off and confiscated mortar shells, a belt of explosives likely to be used by a suicide bomber, 27 wire communications sets, rocket propelled grenade launchers and magazines of bullets.

Iraqi security forces detained 77 people across Iraq during the last 24 hours, the statement said.

Also Friday, gunmen attacked a convoy of civilian trucks carrying unspecified goods had just left Baghdad for the northern city of Irbil. The attack occurred in Taji, 12 miles north of the capital, and left one guard traveling alongside in an SUV was killed, said police Lt. Ahmed Al-Qaisi.

Iraqi police found five bodies with gunshot wounds in Mahmoudiya, about 20 miles south of Baghdad, and a roadside bomb killed one person in Balad Ruz, 45 miles northeast of Baghdad.

Six more bullet-riddled and tortured bodies of men were found in the Tigris river 25 miles south of Baghdad.

A government statement said private vehicles will be banned from streets in about 16 neighborhoods of Baghdad starting Friday night until Monday 6 a.m. during a Shiite religious ceremony marking the death in 799 A.D. of Imam Moussa Kadhim, one of the 12 major Shiite saints. He is buried in Baghdad's Kazimiyah district.

The ceremony, which is expected to bring tens of thousands of Shiites from across the country, reaches its high point Sunday.