( Reuter )- At least 46 people were killed in violence across Iraq on Tuesday, including 14 mourners from one family when a roadside bomb hit a bus in a southern province, security officials said.
In the southern city of Kut, members of anti-U.S. Shi'ite cleric Moqtada al-Sadr's Mehdi Army fought Iraqi security forces in clashes in which 14 people died, security officials said. Sadr said last month he had renewed a ceasefire.
Violence has fallen across Iraq by 60 percent since last June, but Tuesday's attacks underlined how fragile the security gains are.
Police at the general hospital in Nassiriya, 375 km (235 miles) south of Baghdad, said the casualties from the roadside bomb included women and children. Survivors said the bomb appeared to target a passing U.S. military convoy.
Police said the bus was carrying members of a family returning from mourning rites for a dead relative in the holy Shi'ite city of Najaf when it was hit about 60 km (40 miles) south of Nassiriya.
"There was blood and human flesh in the bus and on the floor. Shoes of men, women and children were everywhere," bus driver Zaji Abdul Hussein told Reuters afterwards.
Rahman Shaker, 60, covered in blood after carrying his badly wounded wife from the wreckage, said a U.S. convoy had just passed on the other side of the road when the bomb went off.
"I saw my wife covered in blood and took her out of the bus," Shaker said. "There were bodies covered in bloody blankets, and people screaming."
In Kut, 170 km (105 miles) southeast of Baghdad, an apparent attempt to arrest a Mehdi Army leader sparked clashes between the militia and the Iraqi security forces in two districts. There were conflicting reports that U.S. troops were involved.
The commander of a quick reaction force in Kut, Lieutenant-Colonel Majid al-Amara, said 14 people had been killed, including four militiamen, three children and a policeman, and 28 wounded.
Much of the fighting was reported to have died down by night-fall although sporadic shooting could still be heard.
Sadr last month renewed a six-month ceasefire for the Mehdi Army, but he issued a statement at the weekend telling followers they could act in self-defence if they were attacked.
In separate clashes north of the capital, police said four Iraqi policemen, four gunmen and a civilian were killed in an attack on a security checkpoint in Mosul, which the U.S. military says is al Qaeda's last major urban stronghold in Iraq.
In Dhuluiya, also north of Baghdad, a suicide car bomber killed five people, including three members of a neighborhood security unit, and wounded 14 in an attack on a checkpoint, police Lieutenant-Colonel Ibrahim al-Jubouri said.
U.S. military spokesman Rear Admiral Greg Smith acknowledged at the weekend there had been an increase in violence in Iraq but said the military did not believe it represented a trend.
Earlier on Tuesday, the U.S. military said a roadside bomb had killed three U.S. soldiers and an interpreter in Diyala province northeast of Baghdad on Monday, the same day a suicide bomber killed five U.S. soldiers in the capital.
Monday's deaths took to at least 3,983 the number of U.S. troops killed in Iraq, the toll nearing 4,000 at a time when setting a timetable for withdrawing troops has become a central issue in the U.S. presidential election campaign.
In Samarra, 100 km (60 miles) north of Baghdad, a mass grave containing 20 decomposed bodies, including six women and five children, was found, police said. Police blamed Sunni Islamist al Qaeda for the deaths.