°®Âþµº

A former US air force mechanic has been jailed for 35 years after attempting to join the Islamic State group in Syria and offering expertise and a trove of classified military information to the militants.

Tairod Pugh from New Jersey was found guilty last year of providing support to IS and of obstruction of justice, before being sentenced on Wednesday by a New York court.

"The defendant turned his back on his country, and the military he once served, to attempt to join a brutally violent terrorist organisation committed to the slaughter of innocent people throughout the world," the US acting Attorney Bridget Rohde said in a statement.

The 49-year-old aircraft mechanic was stopped by authorities at a Turkish airport coming from Egypt carrying a laptop with information on how to cross the border into IS-held Syria.

On his computer were also jihadi videos including beheadings.

An undercover FBI agent posing as an IS sympathiser allegedly questioned Pugh at the airport, according to the Daily Beast, before he was detained.

He told his wife his intentions of joining IS saying he had only the option of "victory or death" once he entered Syria, presecutors said.

Pugh was returned to Egypt by Turkish authorities after they suspected his intentions of trying to join IS, according to CNN.

He denies he attempted to join the group and said his visit to Turkey was purely innocent.

The veteran served in the US air force between 1986 and 1990, working on aircraft engines, weapons and navigating systems.

He converted to Islam and became attracted to jihadi interpretations, with colleagues saying he expressed sympathy for Osama bin Laden and al-Qaeda.