A Vietnamese man has pleaded guilty to US terrorism charges after accusations that the man received military training from al-Qaeda’s branch in Yemen.

Minh Quang Pham, 33, pleaded guilty in Manhattan federal court on Friday and now he faces at least 30 years in prison.

Pham, who went to Yemen to join al-Qaeda in the Arabian Peninsula in 2011, learned to use firearms.

He also admitted that he had provided material support to al-Qaeda and the group's online propaganda magazine, Inspire.

According to prosecutors, Pham was trained with Anwar al-Awlaki, a US citizen who was killed in a 2011 US drone attack.

Assistant US Attorney Sean Buckley said that Pham admitted that al-Awlaki taught him how to make an explosive device out of household material.

He was instructed in Yemen to detonate an explosive at London's Heathrow Airport, Buckley said.

Al-Awlaki "directed Pham to return to the United Kingdom, where he was to construct and detonate the device at the arrival area of Heathrow," he noted.

The trial came a few days after an American citizen inspired by the al-Qaeda group was charged on Wednesday with plotting to attack a US military base in Afghanistan.

Muhanad Mahmoud al-Farekh, 30, is accused of conspiracy to murder US nationals, conspiracy to use weapons of mass destruction and other crimes.