A car bomb in the holy city of Karbala, southwest of the capital, Baghdad, has killed at least 15 people and wounded dozens of others, local officials said.
The bomb reportedly went off near the city's central bus station. Smoke could be seen rising from the blast site and cars in the area were on fire.
The attack occurred around 0930 local time, when many people were returning to work after the weekend.
The city is home to two of Shia Islam's most important shrines and has been attacked on several occasions. In January, 49 people died when a bomber blew himself up on a street near the Imam Hussein shrine.
Meanwhile in Baghdad, a car bomb targeting an Iraqi army patrol in the mainly Sunni Adhamiyah area killed at least eight people and wounded several.
Another car bomb aimed at a police patrol exploded at one of the city's major intersections, killing at least one person and wounding five others, reports say.
Iraqi police also found the bodies of at least 42 men in various areas of Baghdad. The men, who had been shot, appeared to have been killed in sectarian attacks, Iraq's interior ministry said.
The attacks come a day after a British helicopter crashed in the southern Iraqi city of Basra, killing four people on board and sparking clashes between British troops and locals.
An Iraqi throws stones at British
troops in Basra on Saturday
The city is said to be calm after the clashes, in which five Iraqi civilians were reportedly killed.
Des Browne, Britain's new defence minister, said the cause of the crash was unclear, but Basra police said the helicopter was downed by a rocket.
Britain has about 8,000 soldiers deployed in Basra.