What is really going on in politics? Get our daily email briefing straight to your inbox Sign up Thank you for subscribing We have more newsletters Show me See our privacy notice Invalid Email

The Saudi Arabian government may have had a role in the 9/11 terrorist attacks according to fresh evidence that has emerged as President Obama lands in the repressive kingdom.

Details of a flight certificate obtained by al-Qaeda bomb maker Ghassan Al-Sharbi have emerged showing he took flying lessons in the United States with some of the 9/11 hijackers.

When he was captured in Pakistan in 2002 investigators discovered the documentation in an envelope from the Saudi embassy in Washington.

According to a US memo, which was written in 2003 and quietly declassified last year, the FBI learnt he had buried a cache of papers shortly before he was captured.

(Image: Reuters)

Known as 'Document 17', it was written by two American investigators examining the possible roles of foreign governments in the attacks.

One of the details Al-Sharb, 41, tried to hide was his US flight certificate discovered in the embassy envelope.

It was only after activist Brian McGlinchey discovered Document 17 and published its details on the internet earlier this week that it was brought to the public's attention.

Read more:

Speaking after the discovery he said: "The envelope points to the fundamental question hanging over us today: to what extent was the 9/11 plot facilitated by individuals at the highest levels of the Saudi government?"

(Image: Reuters)

The emergence of the details, which has fuelled concerns the Saudi government may have been linked to the coordinated attacks which killed nearly 3,000 people, puts increased pressure on Mr Obama as he touched down

in Riyadh earlier today.

He is due to meet King Salman, whose is battling low oil prices and Washington's tougher stance on the country's human rights record.

Video Loading Video Unavailable Click to play Tap to play The video will start in 8 Cancel Play now

Last week the Saudi government threatened to ditch £522 billion in US Treasury securities and other American assets if Congress passed a bill that would allow the families of 9/11 victims to file lawsuits against the

kingdom.

Hillary Clinton and Bernie Sanders, the Democratic presidential candidates, backed the bill, which Mr Obama has signalled he will veto.

(Image: Getty Images)

The US President also faces calls to release a redacted 28-page portion of a joint congressional report on the 9/11 attacks, produced in 2002 and thought to link senior Saudi figures to the plot.

Fifteen of the 19 9/11 hijackers were from Saudi Arabia while then Al-Qaeda leader Osama bin Laden, who was killed in 2011, was the son of a billionaire with close ties to the country's royal family.