Explosions and gunfire were heard in central Kabul near the Presidential Palace and other official buildings Tuesday, media reports said.
Up to 16 blasts were heard, and smoke was rising from near the palace, Arman Radio reported.
Some of the blasts were near the offices of the CIA and the headquarters of the NATO-led international troops, dpa reported.
A gun battle was also reportedly in progress near the Italian embassy.
Armed men were clashing with bodyguards of President Hamid Karzai, and with US personnel from the CIA station, the BBC reported.