A London web designer faces life imprisonment in the US on charges that he provided propaganda and technical expertise to al-Qaida and met terrorist operatives in Yemen.

Minh Quang Pham, 29, is accused of helping produce the group's online English-language "magazine" Inspire, which has featured instructions on how to manufacture explosives and is thought to have been used by terrorist suspects in Britain and the US.

Using the pseudonym Mohammed Amin, Pham is said to have pledged an oath of allegiance to al-Qaida in the Arabian Peninsula, and received military-style training from the group after travelling to Yemen in December 2010.

Pham is a British national of Vietnamese origin, who converted to Islam are moving to the UK as a child. In September 2010, he set up a company designing websites and leaflets which was registered to his home in New Cross, South London, where he has lived since 2005.

Pham was arrested at Heathrow last July as he returned from Bahrain, when a live ammunition round was found in his possession.

He was re-arrested on a US extradition warrant last week, and is currently in custody in Belmarsh maximum security prison awaiting extradition proceedings. He will appear at Westminster magistrates court in August for his next hearing.

In an indictment released by the US Department of Justice, Pham is accused of providing material support to AQAP, based in Yemen, along with others "known and unknown".

Pham is said to have "facilitated communications and provided expert advice and assistance in photography and graphic design" for AQAP's media wing before returning to Britain the following October.

He allegedly met two American citizens, referred to as "American CC-1" and "American CC-2", and worked with the first to produce online propaganda for AQAP.

Those individuals are understood to be Anwar al-Awlaki and Samir Khan, both US citizens who were running AQAP's propaganda operation at the time.

The first edition of the magazine included a recipe called "How to Make a Bomb in the Kitchen of Your Mom" by the "al-Qaida Chef" which was later found in the possession of several terror suspects in Britain.

Al-Awlaki and Khan were both killed in a drone attack in Yemen last September.

Pham is also accused of providing "personnel, property, services, facilities, communications equipment, expert advice and assistance, training and weapons" to al-Qaida.

In return, he is alleged to have received training from AQAP in the use of an automatic Kalashnikov assault rifle between March and June last year.

According to the charges, Pham is said to have known that AQAP "had engaged and was engaging in terrorist activity".

He is also accused of helping al-Qaida "design and disseminate its propaganda" and providing "expert advice and assistance in photography and graphic design".

Members of Minh's family confirmed he had visited Yemen, but denied he was a terrorist.

They said they feared the charges were based on testimony, possibly obtained under duress, from Ahmed Warsame, an al-Qaida leader with links to AQAP and its Somali affiliate Al-Shabaab.

Warsame pleaded guilty in a US court to terrorism offences following his capture on a boat off the coast of Yemen in April 2011. "Minh says he has never met this person," the relative told the Sunday Times.

Jonathan Evans, the director general of MI5, warned last week that Yemen had become a destination for British "would-be jihadis" seeking to gain terrorist training.

Janice Fedarcyk, Assistant Director-in-Charge at the FBI said: "The defendant not only allegedly pledged an oath to al-Qaida in the Arabian Peninsula, and received military training from AQAP, he also helped design and disseminate its propaganda."

A Home Office spokesman said: "Pham, who is wanted in the US for terrorism-related offences, was arrested in the UK on 29 June and has been remanded in custody. He will appear in court in due course."