India has offered help to the Malaysian government to search for the missing Malaysia Airlines jet which vanished two days ago with 239 people on board.
There are five Indian passengers on the flight, the airline says.
The Boeing 777-200ER that mysteriously vanished south of Vietnam without sending a distress call was carrying passengers of 14 nationalities.
The search for the jet by a multinational team has entered its third day.
Relatives of the missing passengers have been told by the authorities to prepare for the worst. There is still no indication of what happened to the plane.
"I have sent my condolences [to the families of the passengers] and our ambassador [in Beijing] is in touch with them. We are ready to give any help, if required, or share information if we get any," Indian Foreign Minister Salman Khurshid said on Sunday.
Family members of the five Indian passengers say they are waiting for any information about the plane.
A relative of Kranti Shirsath, one of the passengers on the flight, said she was on her way to China to meet her husband.
"She was going there on the (International) Women's Day for two months to spend the summer vacations with him. His contract... [with the company where he works] is about to expire. They wanted to settle here in India," KV Shirsath told Reuters news agency.
Kranti Shirsath's son told The Indian Express newspaper that the family was hoping that the plane was recovered.
"We hope the plane has been hijacked, then there is [a] chance that mom will come back," Rahul Shirsath, 16, said.
Samved Kolekar, whose father, mother and brother were travelling by the flight from Kuala Lumpur to Beijing, said he was waiting with his wife in Beijing for news about the flight.
"They were coming to visit me here," Mr Kolekar told the Press Trust of India news agency.
Chandrika Sharma, who works for the Chennai-based International Collective in Support of Fish Workers, was also travelling on the flight to attend a conference in Mongolia, reports said.
"I still believe my daughter will come back," her mother Shakuntala Sharma told a news channel.
An investigation into the cause of its disappearance is focusing on two passengers who boarded the flight using stolen passports.
Malaysian military officials said on Sunday that the plane may have turned back from its scheduled route shortly before vanishing from radar screens, further deepening the mystery surrounding its fate.