Baghdad ? A suicide bomber boarded a minibus and blew himself up Monday in a Shiite-dominated neighborhood of the Iraqi capital, killing 20 people and injuring 18, police and hospital officials said.

It was the latest sectarian salvo to shake the foundations of Iraqi society and government. At least 43 other Iraqis were reported killed in bombings, shootings and other violence across the country.

Meanwhile, U.S. forces raided a mostly Shiite neighborhood on the northwestern edge of Baghdad late Monday, trading gunfire with followers of radical Shiite cleric Muqtada al-Sadr, Iraqi police said.

U.S. jets rumbled overhead, firing rockets. At least six people were killed and three injured, according to police. Iraqi forces helped cordon off the area but did not participate in the raids, they said. The U.S. military had no immediate comment.

Insurgent attacks continued to take a toll on U.S. and British forces.

The U.S. military reported the deaths of four soldiers, bringing to at least 31 the number of troops killed in Iraq this month. Two died and two were injured Monday morning when a roadside bomb exploded in Baghdad, the military said. Another two were killed and two injured in a Sunday suicide car bombing in Salahuddin province, north of the capital.

Four British troops were killed and three wounded the same day when an explosive device hit a boat patrolling the Shatt al Arab waterway, the military said. It was the first time British forces near Basra, Iraq’s second-largest city, were targeted in this way, a spokesman said.

The bomb in Baghdad’s northeast Shaab neighborhood ripped through a busy intersection where Nasir Hawi was selling cigarettes and soft drinks.

“There was a huge explosion that shook and dropped everything in my booth,” said Hawi, 35, propped up in bed in a crowded emergency ward, his head wrapped in bloodied bandages. “I saw more than six cars ablaze and several people, including women in abayas, on the ground.”

“This area has witnessed several other explosions,” he said. “But always the victims are innocent people who are trying to make a living. May Allah curse the perpetrators of such deeds.”

Elsewhere in and around Baghdad, the bullet-riddled bodies of 28 men, many cuffed, blindfolded and bruised, were discovered, police said. Thirteen were found in a mostly Shiite east Baghdad neighborhood, 10 in a Sunni-dominated western part of the city and five in Mahmoudiya, south of the capital.

To the north, in Mosul, a camera operator for Iraq’s independent Al-Sharqiyah television station was gunned down as he left his home, a journalists’ association reported. Mohammed Ban, 58, was the second journalist from his company to be killed in two weeks.

At least 89 journalists have been killed in Iraq since the war began in 2003, according to an Associated Press count based on statistics kept by the New York-based Committee to Protect Journalists. Another 35 support staffers, including drivers, interpreters and guards, have been killed.