At least 19 people are reported to have been killed and 39 others wounded in four bombing and shooting attacks in southern Afghanistan.

Officials said Gunmen begin attacking in three locations in Kandahar, in southern Afghanistan, on Monday, sparking a two-hour gunfight with Afghan security forces.

"Fourteen attackers, some of them equipped with explosive suicide vests, were killed in today's gunfight with Afghan forces," Kandahar Governor Toryalai Weesa told a news conference after the gunfight ended.

The first attack began when three assailants - part of the group of 14 - triggered a bomb on a motorbike, killing themselves and two children.

The children were aged between eight and 12 and were playing at the time of the explosion, an official said.

Minutes later, several others attacked Kandahar's police headquarters and a private bank. Weesa said that three policemen were killed in attacks while 24 other, including 18 police officers, were wounded.

The shooting was followed by two explosions at the entrance of the headquarters. The Taliban militants took responsibility for attacks in Kandahar city.

The attack on the police headquarters, about three kilometres away, began with an explosion and continued for around an hour after at least three fighters took over a nearby school and fired on police, officials said.

The Taliban, whose regime was toppled by a US-led invasion in 2001 after the 9/11 al-Qaeda attacks on the United States, are fighting to oust the Western-backed government of President Hamid Karzai.