British police stopped what looks like a planned attack on an air base housing U.S. bombers, a win for intelligence services but a sign of rising risk to American facilities in Europe.

• Five men in their early twenties were arrested near RAF Fairford after three suspicious vans were spotted heading toward the base, which hosts 125 U.S. personnel and B-1 and B-2 bombers.
• Police evacuated 85 homes and sealed off the area while bomb experts checked the vehicles; the men face terrorism and explosives charges.
• Trump said the plot would have done "big damage" and credited long-running joint surveillance with British authorities for catching them.
• Early speculation ties the group to Iran's Revolutionary Guard, since the base was used in operations against Iran and Tehran is under heavy economic pressure — but nothing is confirmed.
• British officials are refusing to discuss the suspects' backgrounds, which is fueling anger at what critics call deliberately soft language around migration and terrorism.

Outlook: More details on who the men are and who backed them should come out in days, and security around U.S. sites in Britain stays tight.