New Delhi, Sept. 29 -- The suspects were detained shortly after midnight on Sunday after police stopped three vans traveling toward RAF Fairford, a U.K.-owned base that has been used by American bombers during decades of conflicts in the Middle East, including the ongoing Iran war.

Investigators have not concluded whether the incident is a state-backed attack. They are investigating a possible link to Iran, Russia or militant groups. Iran has denied involvement.

Details about the case are still emerging. Here's what we know - and don't know - about what happened:

The identities and motives of the suspects are unclear

Counterterror police said Monday that the five suspects are British nationals from London between 23 and 25 years old....