Police hunting two men who tried to abduct an RAF serviceman at knifepoint say they have not ruled out terrorism as a motive.
They also say there may have been an element of “pre-planning” in the attack near RAF Marham in Norfolk.
The suspects, both of Middle Eastern appearance, approached the man at around 3pm on Wednesday while he was out jogging about a mile from the base.
One of them grabbed him and tried to drag him towards a nearby car but the serviceman, who is married and in his 20s, knocked him to the ground.
His accomplice, who was carrying a knife, helped him up and the pair drove off in a dark-coloured people carrier.
The serviceman, who was not in uniform, was said to have been “very, very shaken by his ordeal”.
Norfolk Police say the suspects are aged between 20 and 30 years old. One had a well-groomed beard and was of stocky build, while the other is clean shaven and slimmer.
Detective Superintendent Paul Durham said: “The motivation for the attack remains unclear at this time, and whilst we are currently unable to discount terrorism, there are a number of other possible hypotheses, including abduction unrelated to terrorism, or robbery.
We have received a number of sightings of the suspect’s vehicle in west Norfolk and there is no reason to discount the chance the the men remain in the area.
“It is hugely important we locate the vehicle and its occupants.”
When asked at a media conference if he thought the attack was pre-planned, Mr Durham replied: “It is difficult to envisage a situation where perhaps there wasn’t an element of pre-planning, but it’s too early to say for sure.”
Enquiries are continuing to confirm the circumstances of the incident.
He added: “It was a regular running route for the victim, it’s a regular running route for a number of personnel within RAF Marham. It’s a well-trodden path.”
The base is home to Britain’s Tornado GR4 Force which is involved in operations in the Middle East.
Detectives have set up a dedicated hotline appealing for information about the two suspects, who are still at large.
A Norfolk Police spokesman said sightings of a dark-coloured people carrier in the King’s Lynn area of Norfolk were of particular interest.
The airbase was on high alert on Thursday, with a roadblock in place on one route into Marham and police patrolling the streets.
However, the airbase’s popular Families and Friends Day was allowed to go ahead, with thousands of people watching a display by the Red Arrows.
The police’s hotline number is 0800 056 0154; people can also call 0207 158 0011.