KANDAHAR, Afghanistan - A suicide bomber on a motorcycle attacked a border police patrol on Monday in southern Afghanistan, killing a policeman, as clashes and a roadside bomb elsewhere left nine people dead, officials said.

Four other policemen were seriously wounded when the bomber struck the police vehicle in the Spin Boldak district of Kandahar province, said border security police commander Gen. Abdul Raziq.

In neighbouring Helmand province, police discovered and tried to defuse a remote-controlled roadside bomb Monday in Nad Ali district, but it exploded, killing two policemen and two civilians, said provincial police chief Mohammad Hussain Andiwal. Four other civilians were wounded.

In the Zhari district of Kandahar, three Taliban militants were killed in a battle between police and NATO troops on Sunday, the Interior Ministry said in a statement. Another militant was detained during the operation, it said.

In neighbouring Uruzgan province, a clash between NATO troops and Taliban insurgents near Tirin Kot, the provincial capital, left two civilians killed and five others wounded on Friday, the alliance said in a statement.

The violence followed a roadside bomb attack on NATO's International Security Assistance Force soldiers, the statement said.

"The dead are a child and an adult; the injured included three children,'' the statement said.

There were no ISAF casualties.

"ISAF sincerely regrets the loss of those civilians and is saddened that casualties were caused as a result of a deliberate attack against ISAF forces that was instigated by the insurgents,'' the statement said.

Civilians are often caught in the line of fire during fighting between the Taliban and international forces or during airstrikes by foreign troops because insurgents hide among civilian homes.

Afghan President Hamid Karzai last year pleaded repeatedly with NATO and the U.S.-led coalition to coordinate more closely with their Afghan counterparts to prevent civilian casualties.

Last year, insurgency-related violence left more than 6,500 people dead -- a record number -- including nearly 900 civilians, according to an Associated Press tally of figures from Western and Afghan officials.