Kabul: At least seven people were killed and 327 others wounded in an ongoing Taliban attack in central Kabul Tuesday, the Afghan health ministry said.

Civilians and members of the Afghan security forces were among those caught in the attack and casualty estimates are expected to rise, ministry spokesman Ismail Kawosi said by telephone.

The attack was aimed at a building that houses a security service that provides protection for government officials.

President Ashraf Ghani condemned the attack ‘in the strongest possible terms’ in a statement from the presidential palace, only a few hundred metres away from the scene of the blast in central Kabul.

The attack began with a suicide car bomb during the height of the morning rush hour, and security forces and militants then exchanged gunfire, Reuters witnesses near the scene said.

Those casualty numbers were expected to rise, said ministry spokesman Ismail Kawosi.

The Taliban announced the beginning of their spring offensive on 12 April, and fighting has raged around the symbolically important northern city of Kunduz since then, although the capital had been relatively quiet.

Kunduz, Afghanistan’s fifth-largest city, fell briefly to the Taliban last September in the biggest blow to Ghani’s government since NATO-led forces ended their combat operations at the end of 2014.

The Taliban said on their Pashto-language website that they had carried out the suicide bombing on ‘Department 10’, an NDS unit which is responsible for protecting government ministers and VIPs.

They said a suicide car bomber blew up the main gate at the front of the office, allowing other fighters, including more suicide bombers, to enter the heavily guarded compound.

Taliban spokesman Zabihullah Mujahid said in a separate statement that the attackers were engaged in a gunbattle with Afghan security forces inside the building.

It was not immediately possible to verify the details of the Taliban’s claim with government officials. The Islamist group often exaggerates details of attacks against government and military targets.

The Taliban-led insurgency has gained strength since the withdrawal of most international combat troops, and the Taliban are believed to be stronger than at any point since they were driven from power by U.S.-backed forces in 2001.

A thick plume of black smoke was seen rising from the area near the sprawling U.S. embassy complex in the centre of Kabul immediately after the blast.

Warning sirens blared out for some minutes from the embassy compound, which is also close to the headquarters of the NATO-led Resolute Support mission.

The U.S. embassy and the NATO mission both said they were not affected by the blast.