Two people were wounded when four Taliban gunmen opened fire in a luxury hotel in the centre of the Afghan capital Kabul at around 6pm, according to police.
There were no details yet on the nationality of the pair.
Security sources said that the armed men entered the Serena hotel by a back door and told them they were going to dinner.
To enter the premises, guests must pass through an exterior gate and undergo a metal detector search and pat down.
Inside, they drew the pistols hidden in their socks and opened fire, Interior Ministry spokesman Sediq Sediqqi said.
Bursts of gunfire could be heard from outside the hotel as Afghan troops cordoned off the area.
A hotel worker named Gulam Ali said that all the guests and
staff members had taken refuge in the basement.
"Everybody's fine," he told his brother Mohammed Nabil, who let an Associated Press reporter listen to the conversation. "Foreigners, workers, everybody is in the basement."
One person who was taken to safety along with other guests said that the shooting appeared to begin in the hotel restaurant.
Another guest, hiding in his room, said he could hear sporadic gunfire.
Taliban spokesman Zabihullah Mujahid claimed responsibility for the assault on the Serena hotel.
"Our people, if they decide to attack any place, they can do it," he said.
United Nations staff and foreign delegations are currently staying at the hotel ahead of next month's Presidential elections, as it is considered to be the safest place to stay in the capital.
Also on Thursday, the Taliban let off a suicide bomb at a police station in Jalalabad , killing 10 officers and a university student.
The attacks come after the Taliban threatened to use violence to the disrupt 5 April elections.
The polls include provincial votes, but the most closely watched is the presidential race. Karzai's successor will guide the country for the next five years as most US and allied forces leave the country by the end of 2014.
Additional reporting by Reuters and AP