The US has not yet made a formal request to use the UK military bases on the island of Diego Garcia in the Chagos archipelago or in Cyprus for potential strikes against Iran.
This has been confirmed by the BBC.
Normally the US would inform London in advance if it intends to conduct offensive operations from these British military bases.
It is believed that US bombers are based at the base on the island of Diego Garcia. The US Air Force regularly sends aircraft to the base.
A British source claims that in London they believe that Washington is considering "all options" for further actions by Trump regarding Iran. But the source said there was no clarity on the US plan.
The US has sent additional military assets to Europe and the Middle East, including refueling tankers, fighter jets and an additional aircraft carrier. The US aircraft carrier "Nimitz" will join the US aircraft carrier "Carl Vinson" already in the Persian Gulf.
A British source described the additional US military assets as defensive - to protect US military bases, personnel and interests in the region.
The UK has also increased its military presence at the Akrotiri air base in Cyprus. Six more "Typhoon" aircraft have been sent there, in addition to the eight "Typhoon" aircraft already stationed at the base.
The additional aircraft will allow the UK to maintain continuous surveillance of British military bases. The US has used the British air base "Akrotiri" in previous military operations.