One of the people arrested on suspicion of terrorism at Heathrow airport may be an NHS doctor.
The Metropolitan Police have confirmed that a man and a woman, both 26, had been taken into custody after arriving on a flight into Heathrow.
They had flown from Egypt and were planning to travel to Syria. It is believed that they were going to fight in the civil war.
Officers are chasing leads to find out if one of the suspects is a doctor who was part of a militant group that held two journalists captive in July.
War photographer John Cantlie and Dutch colleague Jeroen Oerlemans were held for a week. After he was released, Cantlie said one of his captors was a British man who claimed to be an NHS doctor.
Police said two addresses in east London were being searched. The two suspects were held under the Terrorism Act 2000. Police have up to 14 days to hold them in custody.