Security at RAF Fairford had already been increased in recent months. U.K. Key points and original sources are listed below.

• Security at RAF Fairford had already been increased in recent months. Protective screens were installed along parts of the perimeter after the base attracted attention as US bombers arrived.S1

• U.K. counter-terrorism police are understood to be investigating a potential link with Iran after an alleged bomb threat against an air base hosting U.S. forcesS2

• British counter-terrorism police are investigating whether Iran was behind a suspected bomb plot targeting RAF Fairford, a British air baseS3