Authorities in Afghanistan say attacks by suspected insurgents have killed three people and wounded at least eight others.

Police say a roadside bomb Saturday in Kandahar province killed three Afghan security guards and wounded at least two others.

In another incident, Afghan officials say six people, including two foreigners, were wounded Saturday when a suicide car bomb exploded near a vehicle convoy traveling through the capital, Kabul. The nationality of the wounded foreigners is not yet known.

There has been no claim of responsibility for either attack.

In the past year, insurgent violence has sharply increased in Afghanistan's south, which is a stronghold of the hardline Taleban, ousted from power by American forces six years ago.

Meanwhile, the U.S. State Department says it is investigating a friendly fire incident in southern Helmand province that killed three British soldiers and wounded two others.

Britain's Defense Ministry says its soldiers were killed by a U.S. air strike. Officials say the incident occurred late Thursday after warplanes were called in to support the British troops battling Taleban insurgents in Helmand.

Some information for this report was provided by AFP, AP and Reuters.