(Adds more killings, blast)
KABUL, May 27 Eleven civilians and 13 policemen were killed in a series of blasts and Taliban attacks in Afghanistan on Tuesday, officials said.
Nine police were killed in Taliban attacks in Shor Abak district of southern Kandahar, provincial police chief Sayed Aqa Saqib told Reuters.
"The Taliban killed five police in an attack on their post and the other four were killed when we sent in reinforcements later," he said.
Three children were killed by a blast while playing near a police station outside Kandahar city, he said, adding the explosion occurred as a Taliban militant was planting the device under a bridge.
Earlier in the day, one woman, a child and six men were killed when a blast hit a bus in Del Aram district of western Farah province, deputy provincial governor Mohammad Younus Rasuli said.
The blast occurred on a road where Afghan and foreign troops have come under similar attacks and ambushes by Taliban insurgents in recent months, he told Reuters.
The other four policemen were killed in an explosion in Logar province south of Kabul, a provincial official said.
In another incident on Tuesday, U.S.-led troops killed several Taliban militants in an operation in Helmand province in the south, the U.S. military said in a statement.
Violence has escalated in Afghanistan in the past two years, the bloodiest period since Taliban's removal from power in 2001.
Some 13,000 people, including more than 370 foreign troops, have been killed during this period.
The violence comes despite the presence of more than 62,000 foreign troops led by NATO and the U.S. military as well as some 150,000 Western-reliant Afghan forces.
The al Qaeda-backed Taliban are mostly active in southern and eastern areas along the border with Pakistan's tribal region where the militants have some bases.
(Writing by Sayed Salahuddin; Editing by Jeremy Laurence)