Afghan officials say a suicide bomber blew himself up near a primary school in the southeastern province of Khost Sunday, killing at least seven people and wounding 36.

Police say the dead included four children and two security personnel.

Authorities say the bomber was attempting to attack a meeting of officials in the nearby district headquarters and detonated his bomb prematurely when he was challenged.  Officials say U.S. troops were in the building, but were not injured.

In another act of violence, officials say a roadside bomb Saturday killed two Canadian soldiers and two Afghans working with the NATO-led force.

Officials said the bomb exploded in the volatile Kandahar region in southern Afghanistan.  They said the two Afghans killed were an interpreter and a police officer.  

Earlier Saturday, Afghan police said three men were killed when rockets hit their house near a local police station in the capital, Kabul.

It was not immediately clear who fired the rockets.  Taliban militants have been waging an insurgency against Afghan government and coalition forces.

Separately, police said a suicide bomber killed three Afghan police officers and two civilians near the city of Kandahar Saturday.  They said the blast injured at least four other police officers and one civilian.

This year has been the deadliest for NATO soldiers in Afghanistan since the invasion to oust the Taliban began in 2001.

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