Meanwhile, Jordan has become the first Arab country to send a fully accredited ambassador to Iraq.
A US military statement said soldiers from the 172nd Stryker Brigade Combat Team discovered a cache of weapons in a warehouse while conducting searches on Friday in Shula and Ghazaliyah, two hotspot areas of Baghdad where support for Sunni fighters runs deep.
The 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 fighters were detained for questioning, it said.
A separate Iraqi statement said soldiers raided the al-Siddiq Sunni mosque in Ghazaliyah on a tip-off and confiscated mortar shells, a belt of explosives likely to be used by a 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.
First Arab envoy
On Thursday, Ahmad al-Lozi, Jordan's ambassador, presented his credentials to Jalal Talabani, the Iraqi president, a statement by the president's office on Friday said.
Al-Lozi arrived on Tuesday with Marouf al-Bakhit, the Jordanian prime minister, who was on a three-day visit, and stayed behind to take up his duties, Talabani's aide, Hiwa Othman, said.
Al-Lozi is the first fully accredited Arab ambassador in Iraq.
Vehicles have been ordered off
the roads from Friday night
Egypt sent an ambassador, Ihab al-Sherif, last year but he was kidnapped and killed in July 2005 before he could present his credentials.
In Friday's other news, armed men attacked a convoy of civilian trucks carrying unspecified goods had just left Baghdad for the northern city of Irbil.
The attack occurred in Taji, 20km north of the capital, and killed a guard travelling alongside in a 4WD vehicle, said police Lieutenant Ahmed Al-Qaisi.
Separately, Iraqi police found five bodies with bullet wounds in Mahmoudiya, about 30km south of Baghdad, and a roadside bomb killed one person in Balad Ruz, 70km northeast of Baghdad.
Six more bullet-riddled and tortured bodies of men were found in the Tigris river, 40km south of Baghdad.
For their part, Iraqi authorities ordered all vehicles off the roads from Friday night for two days in more than a dozen Baghdad neighbourhoods.
A government statement said private vehicles will be banned from streets in about 16 neighbourhoods of Baghdad from Friday night until Monday 6am during a Shia religious ceremony marking the death in 799 AD of Imam Moussa Kadhim, one of the 12 major Shia imams.
He is buried in Baghdad's Kazimiyah district.