Four people were arrested under anti-terrorism legislation at Manchester airport.
Two men, ages 48 and 23, and two women, ages 48 and 27, were arrested under section 15 of the Terrorism Act on suspicion of providing money or property for terrorist purposes, police said.
A spokeswoman said they were being questioned at a police station in the Manchester area.
The spokeswoman said it was not immediately clear whether the arrests were linked to last month's bombings in London, the AP reported.
Russian small missile ships - the Grad Sviyazhsk and the Great Ustyug - set off for a mission to the Mediterranean Sea