Police investigating the attempted abduction of a serviceman near a Royal Air Force base said Thursday they were unable to rule out terrorism as a motive.

The serviceman, in his 20s, was targeted Wednesday by two men in a car while jogging near RAF Marham air base in Norfolk, England. One of the culprits was armed with a knife.

British military personnel have been on heightened alert since soldier Lee Rigby was beheaded on a London street in 2013. Earlier this year, a British delivery driver with links to a suspected ISIS militant was convicted of plotting a “terrorist” attack against U.S. military personnel based in England.

The intended victim of Wednesday’s attack, who was off-duty and not in uniform, was uninjured. The first attacker shouted but the serviceman did not hear what was said because he was wearing headphones.