(CNN) -- A U.S. military plane carrying three U.S. senators and one member of the House of Representatives came under fire Thursday night as it left Baghdad, Iraq, but it was not hit and flew safely to Amman, Jordan.

Clockwise from top left: Sen. James Inhofe, Sen. Mel Martinez, Rep. Bud Cramer, Sen. Richard Shelby

A Pentagon source said the small-arms fire appeared to be random and came from too far away to hit the C-130 transport.

On the flight were Sens. Richard Shelby, R-Alabama; Mel Martinez, R-Florida; James Inhofe, R-Oklahoma; and Rep. Bud Cramer, D-Alabama.

Shelby described the situation as "kind of dicey."

"We were shot at by three rockets," Shelby said in a statement Friday. "It was dark as the dickens, and I was looking out the small window on the plane and I saw a shell. We saw them, they were popping, and we saw the flares."

The flares are part of the missile avoidance system aboard the C-130 aircraft. The heat from the flares are a countermeasure to attract rockets that have heat-seeking guidance systems.

Shelby added that the plane "started maneuvering, changing directions, shaking us all around, and then I saw another shell near the plane. It's a hostile area, it was a tough area, but the flight crew was very professional; they really did a tremendous job."

Cramer, in a separate statement, said, "Our plane leaving Iraq was fired upon, and it was a close call, but this is something that our men and women in combat face every day. The flight crew was outstanding, and I credit them for the way they handled the situation."

Multi-National Force-Iraq, in a statement issued Friday, said the C-130 crew "dispensed flares as a defensive countermeasure and conducted standard evasive maneuvers. The aircraft, crew and passengers safely completed their flight."

In Baghdad, Iraq's government expressed hope that Shiite cleric Muqtada al-Sadr's decision to suspend the activities of his Mehdi Army militia for six months will prompt other armed groups to follow suit.

Prime Minister Nuri al-Maliki's office issued a statement Thursday welcoming al-Sadr's announcement, made in the aftermath of clashes between Shiite militias in Karbala, Baghdad and Babil province.

Security officials said there was fighting between elements of the Mehdi Army and Badr Organization, the armed force of the rival Supreme Islamic Council of Iraq. More than 50 people died this week as fighting broke out during a Shiite pilgrimage to the southern city of Karbala.

"This initiative is an encouraging step toward consolidating security and stability throughout the country and an opportunity for the suspension of the work of the rest of the militias in various political and ideological affiliations to preserve the unity, independence and sovereignty of Iraq," al-Maliki's office said.

Al-Sadr's political movement "will remain active" and "a true partner in the political process," al-Maliki's office said.

On Friday, four policemen were killed and five people were wounded in a car bombing in northern Iraq, police said. The explosive detonated near a convoy in Samarra, said police in that Salaheddin province city.

U.S.-led coalition troops on Friday killed five insurgents and detained 13 others in raids across Iraq, the U.S. military said.

The five were killed and five were detained southwest of Balad in Salaheddin when troops targeted an al Qaeda in Iraq leader.

"Intelligence reports indicate he recently assumed a position coordinating terrorist logistics between Baghdad and Mosul, and may be trying to obtain chemical weapons for use in attacks against coalition forces," the military said.

The military did not say whether the al Qaeda in Iraq member was killed or detained.

Other raids occurred north of Tarmiya, in Baiji in the north and in Baghdad, where a suspected key leader in the city's car-bombing network was detained, the military said.

On Wednesday, U.S. Marines, backed by air support, killed 12 men believed to be al Qaeda in Iraq terrorists in Anbar province, the U.S. military said Friday.

According to the military, the Marines engaged a group of men loading objects into three cargo trucks near Karma, a town about 40 miles (64 kilometers) west of Baghdad.

Marine Corps Harrier jets were called in and dropped two precision-guided bombs, destroying two vehicles. Marines said they found weapons and bomb-making materials at the scene.

Also, a U.S. Marine and soldier were killed in separate attacks Wednesday in Anbar, the military said. Both were assigned to the Multi-National Force-West.

The U.S. military death toll in the Iraq war stands at 3,730; seven civilian contractors also have been killed. The military has reported 79 U.S. troop deaths during August, matching last month's toll.

Those figures are lower than fatalities in the previous three months, when there were 100 U.S. deaths in June, 126 in May and 104 in April.

Meanwhile, about 1,500 detainees will be released from Iraqi prisons during the Muslim holy month of Ramadan, a statement from the office of Iraqi Vice President Tariq al-Hashimi said.

About 50 people per day will be set free from "American prisons," al-Hashimi adviser Omar al-Jabouri said.

Goodwill gestures are common during Ramadan -- a monthlong observance of daytime fasting and prayer that will begin around September 12. E-mail to a friend

CNN's Raja Razek contributed to this report.

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