Authorities say a roadside bomb has ripped through a minibus in western Afghanistan, killing at least 21 people.

Thursday's blast took place in the Obe district of Herat province. Afghan officials say women and children were among those killed. At least 12 people were wounded in the attack.

A spokesman for Herat's governor says another roadside bomb hit a vehicle in the same district early Thursday, wounding four people.

Afghan President Hamid Karzai and NATO condemned both bomb attacks, which were blamed on Taliban insurgents.

Meanwhile, Afghan officials say two security guards were killed when a suicide bomber detonated a truck full of explosives outside a U.S.-run provincial reconstruction team base in Gardez, in the eastern province of Paktia.

Several others were injured in the blast.

The Taliban claimed responsibility for the attack, saying a 70-year-old militant carried out the bombing.

Meanwhile, local officials in Afghanistan's southern Kandahar province say a shootout between Afghan army and police officers Wednesday evening left three officers dead and at least five civilians wounded in the crossfire. Afghan officials say they are investigating the cause of the fight.

Violence in Afghanistan is at its worst since the U.S.-led invasion in late 2001, with international troop and Afghan civilian deaths reaching record levels.