British Prime Minister Andy Burnham spoke on Monday.

He said there was a suspected plan to attack a U.S. air base in England.

He said Iran's Revolutionary Guard "almost certainly" directed it.

He told lawmakers the plan was probably organized in Iran.

He also said Britain will not accept these threats on its land.

The target was RAF Fairford.

American bombers use it to attack Iran in the war.

Police have arrested seven men.

They are all in their 20s.

All of them have been released on bail.

No one has been charged.

Six are British citizens.

One has both U.K. and Iranian citizenship.

On Sept. 27, many people near the base had to leave.

Armed police and army bomb experts went into the area.

Police later said they found gasoline in three vans.

The vans were linked to the first five suspects.

But they found no explosives.

Iran says it was not involved.

But Iran has said it sees any base used to attack its land as a fair target.

Britain called the Iranian ambassador on Monday.

He said again that Tehran was not involved.

He asked the U.K. to give evidence.

Britain also put two Iranians on its sanctions list.

One is the head of secret operations against spies in the Revolutionary Guard.

The Pentagon said the U.S. moved its bombers from RAF Fairford last week.

They went back to their home bases.