Afghan officials say suicide bombers have killed three people in the capital city.
The Taliban has claimed responsibility for the early Friday attacks targeting a British cultural center and a United Nations compound in Kabul.
Police say a gunfight is underway between assailants and security forces.
On Thursday, authorities say a roadside bomb ripped through a minibus in western Afghanistan, killing at least 21 people.
That explosion 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 Thursday's 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 wounded in the blast.
The Taliban claimed responsibility for the attack, saying a 70-year-old militant carried out the bombing.
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.