Three American service members and a USinfo-icon contractor have been killed when their convoy hit a roadside bomb near Bagram Airfield, the main US base in Afghanistaninfo-icon, the US says.

In a statement Monday, the Afghan military said three other US troops were wounded in the explosion and were receiving treatment.

The Taliban has claimed responsibility for the attack and described it as a suicide car bombing, rejecting the US forces' account of the incident.

The group said an attacker detonated his explosives-laden vehicle near the base in Parwan province.

Iranian mediainfo-icon reports have described those killed in the attack as "American terrorists."

Located in Bagram district in northern Parwan province, the base serves as the main US air facility in the country.

The fatalities bring to seven the number of US soldiers killed in Afghanistan so far this year.

Last year, 13 US service members were killed in the country.

The Taliban stormed an Afghan armyinfo-icon base in Helmand as talks with the US are temporarily halted in Dohainfo-icon.

The Taliban have continued to carry out daily attacks on Afghan security forces despite holding several rounds of peace talks with the United Statesinfo-icon in recent months.

The Taliban's five-year rule over at least three quarters of Afghanistan came to an end following the US-led invasion of the country in 2001. But 18 years on, Washington is still entangled in the warinfo-icon and is now seeking a truce with the militants.