An Afghan police officer investigates a vehicle after it was hit by bomb in Kandahar province on Saturday. (Allauddin Khan/Associated Press)

A series of violent incidents killed four people in Afghanistan Saturday, including a nine-year-old boy, said Afghan officials.

The boy was killed when a bomb placed on a bicycle outside of Kandahar city exploded as a police vehicle passed by, said police. The blast injured four other people.

Police official Mohammad Yaqub told Reuters the bomb was detonated by remote control and that three of the injured were police officers.

In eastern Paktia province, a roadside bomb killed three civilians, said a government spokesperson.

Militants fire at NATO helicopter

Also Saturday, suspected Taliban fighters fired at a NATO helicopter carrying a provincial governor in southern Afghanistan, said Reuters.

The helicopter made an emergency landing, said the report. It was carrying Golab Mohammad Mangal, the governor of Helmand province.

The attack happened near the town of Musa Qala, a former Taliban stronghold.

British military officials confirmed a helicopter from the NATO-led mission made an unscheduled landing, said the report. Britain provides the bulk of the troops in Helmand province.

More than 2,500 Canadian soldiers are serving in the southern Kandahar province. Since the start of the mission in 2002, 83 Canadian soldiers and one diplomat have been killed.

With files from the Associated Press