US drone strike hits IS suicide bomber in Kabul: officials

American forces launched a drone strike in Kabul on Sunday targeting a suicide bomber in a vehicle who was aiming to attack the airport, US officials said, as the United States nears the end of its military presence in the city.

The strike is the second carried out by US forces in Afghanistan since a militant Islamic State (IS) group suicide bomber struck the airport on Thursday, killing 13 US troops and scores of Afghan civilians trying to flee the country.

There were few initial details about the incident, as well as a rocket that struck a neighbourhood just northwest of the airport, killing a child. The Taliban initially described the two strikes as separate incidents, though information on both remained scarce and witnesses heard only one large blast on Sunday in the Afghan capital.

On Saturday, US President Joe Biden said the situation on the ground remained extremely dangerous, and that his military chiefs had told him another militant attack was highly likely within the next 24-36 hours.

US officials had said they were particularly concerned about the local affiliate of IS attacking the airport as American troops depart, in particular the threat from rockets and vehicle-borne explosives.

One US official said Sunday's strike was carried out by an unmanned aircraft piloted from outside Afghanistan, and that secondary explosions following the strike showed the target had been carrying a "substantial amount of explosive material".

Witnesses reported an explosion near the airport and television footage showed black smoke rising into the sky.

Two witnesses said the blast appeared to have been caused by a rocket that struck a house in an area to the northern side of the airport, but there was no immediate confirmation.

Following Thursday's suicide bombing, the US military launched a drone strike on Friday that it said targeted members of the group in Nangarhar province, east of Kabul.

That strike killed two "high-profile" IS-Khorasan planners and facilitators and wounded another, the Pentagon said.

US military cargo planes continued their runs into the airport on Sunday, ahead of a Tuesday deadline earlier set by President Joe Biden to withdraw all troops from America's longest war.