A series of explosions rocked one of the most secure areas of the Afghan capital early Tuesday in an attack outside the presidential palace while reporters were present for a press event with President Hamid Karzai, Reuters reported. Explosions and gunfire reportedly shook the city center and debris was visible.

"Taliban militants attacked key buildings near Afghanistan's presidential palace and the U.S. CIA headquarters in Kabul, a brazen assault that could derail attempts for peace talks to end 12 years of war.

The Taliban, who have said they are willing to take part in talks with the United States and Afghan President Hamid Karzai's administration, said they launched the early morning assault, which triggered a 90-minute firefight.

A U.S. envoy was in Kabul on Tuesday to try to smooth the way forward for the stalled talks in the Gulf state of Qatar ahead of the pullout from Afghanistan of most of the NATO-led troops next year. He had been expected to meet reporters at the palace.

Karzai was also due to attend, but his whereabouts were not known. A palace official said he was safe."

The area is also home to the Ministry of Defence and an annexe of the U.S. embassy at the old Ariana Hotel.

Afghan forces and U.S. servicemen returned fire killing 3 or 4 of the Taliban attackers, and another was killed when he detonated an explosive device attached to his body. At least 2 Afghan security guards were killed, and explosions resounded through the area as children walking to school were caught in the shooting, but escaped serious injury.