An Assyrian Orthodox priest was killed in a drive-by shooting Saturday in Baghdad, police and an assistant said, the latest attack against Iraq's Christian minority.

The priest, Youssef Adel, was shot by gunmen who drove up in a car and opened fire as he was opening the gate of his house near the St. Peter and Paul church where he presided, an assistant said.

Christians have frequently been caught up in the violence or been targeted in this predominantly Muslim country.

The body of Archbishop Paulos Faraj Rahho, one of Iraq's most senior Chaldean Catholic clerics, was found on March 13, about two weeks after he was seized by gunmen in the volatile northwestern city of Mosul.

Adel's assistant, who spoke on condition of anonymity because of security concerns, said the attack occurred about 11:30 a.m. and the gunmen fled the area in a car after the shooting.

He said the priest was in his early 40s and was married but had no children.

Adel was an engineer but became a priest about six years ago. He previously served in a church in the predominantly Sunni area of Dora in southern Baghdad but moved to the central primarily Shiite district of Karradah after a series of attacks in the former insurgent stronghold.

The assistant said Adel was a compassionate man who preached about love and peace and was heavily involved in helping orphans and widows in his church.

"We are paying the price of the insecurity hitting this country," he said.

Elsewhere in Baghdad, a bomb exploded on a minibus carrying morning commuters on the busy Palestine Street, killing at least four passengers and wounding 15, police said.

The victims were primarily workers and vendors from the Sadr City district who were on their way to commercial areas elsewhere in the capital.

The killings underscored the dangers that continue to face Iraqis in Baghdad and elsewhere as attacks persist despite a sharp decline in violence over recent months amid a U.S.-Iraqi security crackdown.

The Iraqi government, meanwhile, eased security measures in two Baghdad neighborhoods that are strongholds of Muqtada al-Sadr's Mahdi Army militia — Sadr City and Shula — amid complaints of food shortages nearly a week after the radical Shiite cleric issued a cease-fire order.

Trucks carrying maintenance teams, food, oil products and ambulances are now allowed to get into the areas, according to a statement issued by Brig. Gen. Qassim al-Moussawi, Baghdad's chief Iraqi military spokesman.

The areas — including Sadr City, which is home to some 2.5 million Shiites and the militia's largest base — have suffered as a vehicle ban remained effect despite the lifting of a curfew elsewhere in the capital earlier this week.

Despite an order by al-Sadr to end to large-scale fighting that broke out over a government crackdown in the southern city of Basra, clashes have continued between his fighters and Iraqi security forces.

Sporadic gunfire was heard in Basra, although it was relatively calm as aid workers delivered humanitarian assistance to the beleaguered residents.

Associated Press Television News footage showed neighbors in the Hayaniyah area examining the rubble of a house they said was destroyed in an airstrike Friday evening in the militia stronghold.

Police said five people were killed in the strike, acknowledging they included an unspecified number of militants who had fired a mortar at Iraqi security forces.

British military spokesman Maj. Tom Holloway said an attack helicopter hit a position from which militants were firing at Iraqi forces in Hayaniyah, but he gave no information about casualties and did not specify whether the aircraft was U.S. or British.

A series of airstrikes have struck suspected militant positions since the fighting erupted on March 25, drawing American and British forces into the battle and casting further doubt on the ability of Iraqi forces to take over their own security.

The White House has conditioned further U.S. troop withdrawals on the readiness of the Iraqi military and police.

Al-Maliki had suggested he planned similar crackdowns in Sadr City and Shula earlier this week, but instead he ordered a nationwide freeze on Iraqi raids against Shiite militants on Friday.

The reversal came after al-Sadr hinted at retaliation if Iraqi security forces continue to arrest his followers.