A powerful explosion has rocked a US military base in eastern Afghanistan and reportedly killed at least 27 American soldiers and left dozens wounded.

Taliban spokesman Zabiullah Mujahid claimed responsibility for the deadly attack, saying the huge explosion left at least 27 American troops killed and 34 others wounded, a Press TV correspondent reported.

The incident occurred early Thursday when a truck bomb went off inside the US military base in Gardez city, the capital of Afghanistan's Paktia province.

According to the Taliban spokesman, the truck contained hundreds of kilos of explosives.

Witnesses say the explosion was very powerful and a US helicopter was also destroyed in the blast.

American forces in Afghanistan have been experiencing their deadliest days since the beginning of August.

On August 6, at least 31 US Special Forces were killed after Taliban militants shot down an American helicopter belonging to NATO's International Security Assistance Force (ISAF) in Afghanistan's eastern province of Wardak.

The death toll was the biggest in a single incident for foreign forces since the US-led invasion of Afghanistan began in 2001.

In another attack on August 11, ISAF said in a statement that six US-led soldiers lost their lives following the explosion of a roadside bomb in volatile southern Afghanistan.

The security situation remains fragile in Afghanistan despite the presence of about 150,000 US-led foreign forces in the war-torn country.

The increasing number of troop casualties in Afghanistan has caused widespread anger in the US and other NATO member states, undermining public support for the Afghan war.

MSH/MB/HRF