Flames rise from a government building after an explosion and attack by gunmen, in Kabul, Afghanistan, on December 24.
CNN  — 

At least 47 people were killed and 25 were injured Monday during a a seven-hour assault that began with a car bomb at a government building in the Afghan capital, authorities said.

A police officer and four attackers were among the dead after the standoff at the National Authority for Disabled People and Martyrs’ Families in Kabul, according to Najib Danish, an Interior Ministry spokesman.

A wounded man receives treatments at the Wazir Akbar Khan Hospital after the car bomb attack in Kabul.

The attack began Monday afternoon with the detonation of a vehicle bomb at the gates to the building, Danish said. Three gunmen then stormed the building, where hundreds were working.

Two police officers were wounded, the official said. At least 350 workers were evacuated and the number of casualties could rise, according to Danish.

Local authorities had earlier said the gunmen took hostages in the building.

Afghan security forces stand guard at the site of the attack in Kabul.

The attack comes at a time when the US military has been ordered to begin planning to withdraw about half the troops in Afghanistan, as a US defense official with direct knowledge of the matter told CNN last week.

The official said planning is underway, and it could take months to withdraw the nearly 7,000 troops.

Gen. John Allen, a former commander of NATO and US forces in Afghanistan, said Thursday that a drawdown in Afghanistan would be a mistake.