Suicide bombers attacked a luxury hotel in the Afghan capital Kabul on Monday, killing at least two guards, a police official said.

Norway's Foreign Minister Jonas Gahr Stoere was staying at the five-star Serena Hotel in the centre of the city at the time of the attack and afterwards hid in the basement and was said to be safe, Norway's public broadcaster NRK said.

A journalist from the Norwegian newspaper Dagbladet was injured in the attack, NRK said.

Two attackers threw hand grenades, killing two guards, to get past the outer security cordon and into the hotel compound where they exploded their vests, the police official said. He said he had no further information on casualties.

The hotel is mainly frequented by foreigners.

"I saw one attacker kill a guard and get through the hotel gate, then there was an explosion," said one man near the hotel.

Hardline Islamist Taliban militants carried out more than 140 suicide attacks in 2007 in their campaign to overthrow the pro-Western Afghan government and drive foreign forces from the country.

Norway's Foreign Ministry said it had received information that all its delegates were safe.

Norway has about 500 soldiers in Afghanistan as part of a NATO-led international force sent there after U.S. and Afghan opposition forces ousted the Taliban government in 2001.

U.S. troops cordoned off the roads around the Serena Hotel, completed in 2006 at a cost of $35 million, partly funded by the Aga Khan Foundation.

A Western security source spoke of one bomber in a car, and said five people, including three hotel guards, were killed.

Another police official close to the scene said the blast had happened inside the hotel compound.