A NATO-led International Security Assistance Force (ISAF) military base came under attack in central Afghanistan's Wardak province on Saturday, causing a significant number of injuries, according to ISAF press release early Sunday.

"A Taliban suicide bomber detonated a large vehicle-borne improvised explosive device at the entrance of Combat Outpost Sayed Abad, Wardak province, yesterday," read the release.

American troops are believed to be based in Sayed Abad district, some 70 km southwest of Afghan capital Kabul.

A statement from the Taliban said the attack was launched by a Paktia resident from east Afghanistan at about 5:00 p.m. local time on Saturday (1230 GMT). The attacker "blew up his truck stuffed with some 9,000 kg explosives" targeting the U.S. base.

According to ISAF, the driver, whose truck was carrying firewood, detonated his explosives at the outpost's Entry Control Point.

Most of the force of the explosion was absorbed by the protective barrier at the outpost entrance and though there were a significant number of injuries, "all are being treated and none is immediately life threatening," the ISAF statement said.

The explosion damaged the compound entrance and was not followed up by any subsequent attacks. "The impact to the compound is readily repairable and operations are continuing," said ISAF.

However, the Taliban statement quoted witnesses as saying more than 50, most of whom were Americans, were killed and several dozens were seriously hurt and being evacuated by the helicopters shortly afterwards. A witness saw the helicopters landing at the blast scene and taking off more than 16 times airlifting corpses and casualties. He added a number of the military vehicles were destroyed in the powerful blast.

The Sayed Abad district was the scene of a deadly helicopter crash on August 6 this year. A total of 30 U.S. soldiers, seven Afghan army commandos and a local translator were killed when the Taliban reportedly shot down the American CH-47 Chinook helicopter during an operation against insurgents.

The Taliban stepped up their attacks on Afghan and NATO-led troops since a spring rebel offensive was launched in May this year in the war-ravaged country.