NEW DELHI: Indian authorities on Sunday described as “speculation” a concern expressed by former US official Strobe Talbott that the missing Malaysia Airlines jetliner may have been hijacked for a 9/11-type attack on an Indian city.A day earlier, Talbott, who was deputy secretary of state in the Bill Clinton administration, had tweeted: “Malaysia plane mystery: Direction, fuel load & range now lead some to suspect hijackers planned a 9/11-type attack on an Indian city.”Theories abound about what may have happened to the 239 passengers on board flight MH 370, which vanished from radar screens on March 8 about an hour after taking off from Kuala Lumpur en route to Beijing. Indian diplomats and security agency officials coordinating with search efforts described Talbott’s tweet as an “educated guess”, even as they did not rule out the possibility.“We are looking into every possibility after various reports emerged that the plane may have flown near the Andamans or may have been hijacked and even flown to Kazakhstan and the Himalayas,” a senior official of the Indian security establishment monitoring the developments told ET.“But it is very speculative at this stage to conclude that it was hijacked for 9/11-type attack on an Indian city.” The probe has turned into a criminal investigation, and the focus shifted to the Indian Ocean and the Bay of Bengal after Malaysian Prime Minister Najib Razak on Saturday said the plane appeared to have been deliberately steered off course after someone on board shut down its communications systems.Referring to the tweet, an Indian official said that Chennai would be the nearest Indian city to target. However, since the plane is believed to have flown for six to seven hours after crossing the Strait of Malacca, there is a likelihood that it would have flown into Central Asia or towards the Gulf, the official added.Satellite signals indicate that the Boeing 777-200 ER flew for 6 hours and 40 minutes from the Strait of Malacca. Meanwhile on Sunday, Malaysia’s defence and acting transport minister, Datuk Seri Hishammuddin Hussein, said it is difficult to label the plane’s disappearance as a hijack or an act of terrorism as no group has made any demand so far.Malaysian authorities also held a review meeting for the envoys of nearly 20 countries, including India, Pakistan, China, Bangladesh, Indonesia, Myanmar, Kazakhstan and Turkmenistan, over whose territory the plane might have flown.India’s High Commissioner to Malaysia, TS Tirumurti, attended the meeting. “The aim of this meeting was to refine the search operations with the assistance of countries over which the flight might have gone.The Malaysian authorities sought corroboration of the findings of their probe so far from these countries, including India. Once this corroboration is done, Malaysia and these countries will enter into operational arrangement to locate the plane,” a senior diplomat in the Indian High Commission in Malaysia told ET over phone from Kuala Lumpur.Zones are being fixed for conducting search operations and one such zone is south of Indonesia, where search operation will be launched shortly. Meanwhile, asuicide bid by the pilots is not being ruled out.Meanwhile on Sunday, Prime Minister Najib of Malaysia called his Indian counterpart to request technical assistance from Indian authorities in corroborating the possible paths that the missing Malaysian airliner might have taken after losing contact with ATC radars, government sources told ET.Singh assured him of all possible assistance. Earlier in the day, India put on hold its search efforts at the request of the Malaysian government after it decided to refine search operations.The Indian Navy and Coast Guard had been combing two areas — one around the Andaman and Nicobar Islands and the other in the Bay of Bengal. “It's more of a pause,” Commander Babu, spokesperson, Eastern Naval Command, said.