President Xi Jinping on Friday extended condolences to Indian President Droupadi Murmu and Prime Minister Narendra Modi over the heavy casualties caused by the crash of an Air India flight.

He also sent a message of condolences to Britain's King Charles III over the heavy British death toll.

Xi's condolences came as rescue teams with sniffer dogs combed the crash site of the London-bound passenger jet that ploughed into a residential area of India's Ahmedabad city on Thursday, killing at least 265 people on board and on the ground.

The airline said there were 169 Indian passengers, 53 British, seven Portuguese and a Canadian on board the flight bound for London's Gatwick airport, as well as 12 crew members.

Only one person aboard the Air India Boeing 787-8 Dreamliner – carrying 242 passengers and crew – miraculously survived the fiery crash, which left the tailpiece of the aircraft jutting out of the second floor of a hostel for medical staff from a nearby hospital.

The nose and front wheel landed on a canteen building where students were having lunch, witnesses said.

Deputy Commissioner of Police Kanan Desai said 265 bodies had so far been counted – suggesting at least 24 people died on the ground – but the toll may rise as more body parts are recovered.

Prime Minister Modi, who on Friday visited the devastated neighbourhood where Air India flight 171 went down, earlier described the crash as "heartbreaking beyond words".

In an unrelated development, an Air India flight from Phuket to New Delhi received an onboard bomb threat on Friday and made an emergency landing on the island, airport authorities said.

All 156 passengers on flight AI 379 had been escorted from the plane, in line with emergency plans, an Airports of Thailand official said.

The aircraft took off from Phuket airport bound for the Indian capital at 9.30am but made a wide loop around the Andaman Sea and landed back on the southern Thai island, according to flight tracker Flightradar24. (Xinhua/AFP/Reuters)