KABUL, Afghanistan -- At least nine people were killed across Afghanistan on Wednesday, including two children who were struck by a bomb blast while gathering firewood, officials said.

The fatal blast took place in the Zhari district of the southern Kandahar province. A separate bomb blast in the Shahwali Kot district of Kandahar wounded another 10 children, leaving seven in critical condition, said Samim Khopalwaq, the spokesman for Kandahar's governor.

"Our children were there to collect wood to burn when they were hit by this bomb," said Bismallah Jan, the father of one of the wounded children. "The government should have cleared the area, it their duty to protect us."

Afghanistan is one of the most heavily mined countries in the world, and children are often killed or wounded while playing, collecting firewood or tending animals.

The deaths of the two children brought the day's toll across Afghanistan to nine dead.

In the eastern Nangahar province bordering Pakistan, a bomb blast killed Judge Mohammad-ul Hassan and wounded two of his daughters in the provincial capital Jalalabad, police spokesman Hazrat Hussain Mashreqiwal said. The judge served in neighbouring Laghman province.

In another attack, insurgents killed six people working on a road project, including the head of a construction company, in northern Baghlan province, police spokesman Jawed Basharat said, adding that the attack wounded another person and left two missing.

In eastern Khost province, three suicide bombers attacked a police academy, with one blowing himself up in a car and the other two shot by police, the provincial governor's office said in a statement. It said three police officers were wounded.

The Taliban claimed responsibility for the attacks in Nangarhar and Khost.

Taliban insurgents have stepped up attacks on Afghan soldiers and police in recent months. U.S. and NATO forces concluded their combat mission at the end of last year and Afghan troops took charge from Jan. 1.