British police on Wednesday said they had arrested two people at London's Heathrow Airport on suspicion of the commission, preparation or instigation of acts of terrorism.
A man and a woman, both aged 26, were detained by officers from the counter-terrorism command at 8.30 pm (1930 GMT) Tuesday after arriving on a flight into the airport, according to a Metropolitan Police statement.
They were being held at a central London police station, police said.
"The arrests form part of an investigation into travel to Syria in support of alleged terrorist activity," added the statement.
Officers executed two search warrants at separate residential addresses in east London in connection with the inquiry.