File photo shows Afghan soldiers running at the site of an attack on a luxury hotel in Kabul, Afghanistan on June 29, 2011. (Xinhua/Ahmad Massoud)

KABUL, Jan. 20 (Xinhua) -- Casualties were feared as gunmen attacked a major hotel frequented by foreigners and senior officials in Kabul, Afghanistan on Saturday night, witnesses and local media said.

"We heard grenade blasts and gunfire in Intercontinental Hotel Saturday night. The whole place has now been sealed off for precautionary measures," an eyewitness told Xinhua.

The Special Operations Forces arrived at the hotel overlooking the city shortly after the incident, he said.

No one knows what is exactly ongoing in the area as security forces did not allow media and people to reach the area.

"There is fear of hostage taking incident, as several people were inside the hotel when the terrorists attacked the multi-story building. Some parts of the building caught fire following the gunfire and explosions," he said.

"We still cannot provide details on causalities. There is fear of possible causalities," security sources were quoted by local media as saying.

No group has claimed responsibility for the attack so far.

Saturday's attack is the second assault against the hotel. In 2011, Taliban militants attacked the same hotel, inflicting high casualties and damage.