KABUL, Afghanistan — Five Taliban fighters were killed early Thursday after they attacked Kabul International Airport, killing a guard and seizing control of a nearby building.

The airport was closed for several hours, and flights were diverted as Afghan security forces battled the militants.

Witnesses said the attackers detonated a truck with explosives in front of the gate of a cluster of residential apartment buildings under construction in an area opposite the airport known as Qasaba. Gunmen then entered an unoccupied building that was still under construction and fired 16 rocket-propelled grenades from the top floor at the airport, the witnesses said.

It was the third and most serious attack on Kabul’s airport in recent months, and it came during an increase in insurgent activity across the country and deep political tension over the disputed presidential election.

A Taliban spokesman, Zabiullah Mujahid, claimed responsibility and named four of the attackers. The terrorist group is largely based in Pakistan, but has focused on staging dramatic attacks on Afghan cities and against Afghan and international security forces.

Witnesses and police officers at the scene said that an Afghan guard on duty at the construction site had been killed and that the gunmen had fired many grenades into the airport compound.

The attack was on the military side of the airport, where Afghan air force facilities and a NATO-run military hospital are based. But it disrupted international flights as well.

By 8 a.m., helicopters were circling over the battle scene, and Afghan counterterrorism forces and quick-response units had swarmed into the area, killing the attackers within an hour. The police said there were five attackers, one of whom was killed in the initial blast and four others who were shooting from the top floor.

Of the four gunmen inside the building, soldiers said they had shot two and that two had detonated their explosive vests and killed themselves.

In a separate attack, a large group of guards from the Presidential Protective Service was ambushed by Taliban fighters in the Zurmat district of Paktia province, said Aimal Faizi, the spokesman for President Hamid Karzai. The guards were traveling to Urgun district, in Paktika, the site of a car bombing Monday, in advance of a visit by Karzai.

There were more than 100 guards in the convoy, Faizi said, and the Taliban appeared to have had a similarly large force. The guards “were surrounded from every corner. They were trapped,” he said.

But air support helped the guards hold their position, and together with army and police reinforcements, they repelled the Taliban by early afternoon, Faizi said. The guards were attacked a second time as they continued on their way.

Preliminary reports from the scene indicated that at least four of the guards were wounded, Faizi said. The Taliban spokesman claimed responsibility for the attack.

In the U.S. on Thursday, the top U.S. commander in Afghanistan told senators that military commanders did not recommend that the White House announce the complete withdrawal of U.S. troops from Afghanistan in 2017 as the president ordered.

Marine Gen. Joseph Dunford said U.S. and Afghan military leaders would have preferred to see American officials be “a bit more ambiguous” about the troop numbers for 2017, and not telegraph to the enemy that international forces would leave.

Speaking before the Senate Armed Services Committee, Dunford laid out a sober assessment of the Afghan security forces, saying there will still be critical aviation and intelligence-gathering gaps in their ability to conduct counterterrorism operations in 2016. He said the current plan requires U.S. forces to shift to Kabul in 2016, significantly reducing U.S. ability to assist in the counterterror fight.

He said if the U.S. decides more help is needed in 2016, officials will have to start discussing that a year from now in order to have American special-operations forces available beyond Kabul to assist in that fight.

Dunford has been nominated to be the next commandant of the Marine Corps and was testifying at his nomination hearing.

Information for this article was contributed by Jawad Sukhanyar, Carlotta Gall, Matthew Rosenberg and Haris Kakar of The New York Times and by Lolita C. Baldor of The Associated Press.