KABUL, Afghanistan — A week after proclaiming their spring offensive, Taliban militants stormed an Afghan government security agency with a suicide car bomb and gunfire Tuesday, killing 28 people and wounding hundreds in a sign of the insurgency's continued strength — even in the capital.
The coordinated attack in central Kabul appeared to have targeted an agency that provides an elite security force for high-ranking government officials, similar to the U.S. Secret Service.
The blast "was one of the most powerful explosions I have ever heard in my life," said police Cmdr. Obaidullah Tarakhail, who was nearby and couldn't see or hear anything for 20 minutes afterward.
"All around was dark and covered with thick smoke and dust," he said.
Taliban spokesman Zabihullah Mujahid claimed responsibility for the attack. On April 12, the insurgents announced the start of their warm weather fighting season, vowing to carry out large-scale attacks in the 15th year of their war against the U.S.-backed government.
The Taliban has remained resilient as the government struggles to confront the violence amid a bitter feud between President Ashraf Ghani and the country's chief executive, Abdullah Abdullah.
Two militants carried out the assault, said Interior Ministry spokesman Sediq Sediqqi. One attacker drove the small truck packed with explosives that caused the initial blast, and he was followed by the second assailant who entered the compound in the chaotic aftermath and opened fire before being killed by security forces, the spokesman added.
"With no doubt, there was a security vacuum, and that needs to be investigated," Sediqqi said, refusing to comment further.
The bomb heavily damaged buildings and vehicles, he said, noting that the death toll of 28 could rise. At least 327 wounded were brought to hospitals, said Ismail Kawasi, a spokesman for the Public Health Ministry.
Abdullah went to the scene and strongly condemned "this act of brutality."
"The government raised the call for peace, but unfortunately the answer by the enemy was fighting, violence, bloodshed, killing innocent people," he said.
After the Taliban began its spring offensive, Abdullah said, "the brave security forces of our country defeated them, and they had many casualties, so today by carrying out such an attack, they wanted to get revenge."
He postponed an upcoming visit to Pakistan because of the attack, said his spokesman, Jawed Faisal.
The U.N. Assistance Mission in Afghanistan also condemned the violence.
"This attack shows the devastation caused by the use of explosive devices in urban areas and once more demonstrates complete disregard for the lives of Afghan civilians," said Tadamichi Yamamoto, the secretary-general's deputy special representative for Afghanistan. "The use of high explosives in civilian populated areas, in circumstances almost certain to cause immense suffering to civilians, may amount to war crimes."
Gen. John W. Nicholson, the commander of international forces in the country, said it demonstrated that "the insurgents are unable to meet Afghan forces on the battlefield and must resort to these terrorist attacks."
Ghani also condemned the attack, saying it "clearly shows the enemy's defeat in face-to-face battle with Afghan security forces," a reference to the military successes against the extremists in the northern part of the country.
Political analyst Haroun Mir said the violence highlighted the inability of the security forces to prevent such a large assault in the heart of the capital, underscoring the depth of the political disarray in the government.
"This shows the weakness of the Afghan security forces that comes out as a result of political problems between both leaders," Mir said. "It is a big question how a truck full of explosive could make it inside Kabul ... very close to the presidential palace."
The bitterness and division in the government stems from a belief in Abdullah's camp that the 2014 election was stolen and given to Ghani because he was seen by Washington as someone with whom it could more easily do business.
In the Taliban's announcement about its spring offensive, the militant group said it would use different tactics to put added pressure on the government, Mir said.
The bloodshed came four days after another Taliban attack in northern Kunduz province that was beaten back by Afghan security forces.
Officials said security has improved in the city of Kunduz and that the Taliban were defeated in other parts of the province, but operations were still underway to clear militant fighters from the rest of the region.
The Taliban held Kunduz for three days last year before being driven out by a two-week counteroffensive aided by U.S. airstrikes. It was their biggest foray into an urban area since 2001.
U.S. and NATO forces formally ended their combat mission at the end of 2014, shifting instead to a training and advisory role while continuing to carry out counterterrorism operations.
There are 9,800 U.S. forces on the ground in Afghanistan, and that number is set to fall to 5,500 next year.
Associated Press writers Amir Shah and Karim Sharifi contributed to this report.