KABUL, Afghanistan — A brazen hours-long coordinated assault on a government building in the Afghan capital of Kabul on Monday killed 40 people, most of them employees of the department for martyrs and disabled persons, said Interior Ministry spokesman Najib Danish. Another 29 people were wounded, including three policemen.

The assault began with a suicide bomber who blew up his explosives-laden car in front of the multi-story building in an eastern neighborhood of Kabul. Within minutes of the powerful explosion three gunmen, armed with assault rifles and explosive devises, stormed the building. For nearly eight hours they rampaged through the office complex terrorizing employees. Some of the employees managed to hide and police quickly evacuated 357 other employees, Danish said.

Witnesses reported hearing at least five explosions as police and gunmen traded fire. One of the dead was a police officer but the rest were civilians, including one women.

Police cordoned of the area as they tried to secure the building but Danish said the operation was painstakingly slow as police went carefully from room to room and floor to floor. All three gunmen were killed.

The attack began as workers were preparing to leave for the day, said Kabul police spokesman, Basir Mujahid. He said at least one telephone call was received from inside the building as marauding gunmen searched for employees, many of whom hid in barricaded rooms. Mujahid said the telephone call was brief and the employees were unable to provide any details.

Mujahid said all they could tell the terrified employees was to wait for help to arrive.

It wasn't immediately known if those who had made the phone call had survived.

Several apartment buildings as well as a government public works department building are located in the same eastern Kabul neighborhood where the attack occurred. Eyewitnesses reported that a portion of the government building was in flames. It smoldered for hours as police tried to locate the dead and wounded. Danish feared the death toll could increase as police continue to search the building. More searching will be done in the daylight hours when he feared the death toll could increase.

No one claimed responsibility but both the Taliban and the local Islamic State affiliate have carried out brazen daytime attacks in the capital.

The attack came just hours after Pakistan's Foreign Minister Shah Mahmood Qureshi was in the Afghan capital to discuss ways of finding a negotiated end to Afghanistan's 17-year war. Qureshi, who travelled to Iran from Kabul, condemned the attack.

Pakistan is taking part in the latest U.S. effort to revive the peace process. It was Pakistan that helped orchestrate last week's talks in the United Arab Emirates. Representatives of Saudi Arabia, the UAE, Pakistan and the United States attended those talks with the Taliban.

The latest violence comes just two days after U.S. President Donald Trump announced half of the 14,000 American soldiers in Afghanistan would be withdrawn by the summer.