By Eveline Danubrata and Nguyen Phuong Linh KUALA LUMPUR/PHU QUOC ISLAND, Vietnam (Reuters) - T he disappearance of a Malaysian jetliner is an "unprecedented aviation mystery", a senior official said on Monday, with a massive air and sea search now in its third day failing to find any confirmed trace of the plane or the 239 people aboard. Vietnam scrambled helicopters to check reports of a floating "yellow object" that rescue teams suspected could be a life raft from the plane, but it was unclear whether the sighting would prove to be the first big breakthrough or merely the latest in a series of false alarms. The head of Malaysia's Civil Aviation Authority, Azharuddin Abdul Rahman, said a hijacking attempt could not be ruled out as investigators explore all theories for the loss of Malaysia Airlines flight MH370 en route to Beijing. "As far as we are concerned, we have to find the aircraft, we have to find a piece of the aircraft if possible." As dozens of ships and aircraft from seven countries scour the seas around Malaysia and south of Vietnam, questions mounted over possible security lapses and whether a bomb or hijacking attempt could have brought down the Boeing 777-200ER airliner.
Ukraine sought urgent Western backing on Monday after Russian President Vladimir Putin insisted that Crimea had the right to join his country even while hinting at a readiness for dialogue. The pro-European team in Kiev that rode the wave of three months of deadly protests to topple a Kremlin-backed regime is running against the clock to preserve the territorial integrity of the culturally splintered nation of 46 million. The self-declared leadership on the predominantly ethnic Russian peninsula of Crimea has proclaimed independence from Kiev and set a March 16 referendum on switching over to Kremlin rule. The decision has been condemned by Western powers who are also furious at Moscow's seizure of Crimea in a lightning but bloodless operation that began days after the February 22 fall and subsequent escape to Russia of president Viktor Yanukovych.