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 239 people aboard. The head of Malaysia's Civil Aviation Authority, Azharuddin Abdul Rahman, said a hijacking 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 could have brought down the Boeing airliner. Interpol confirmed on Sunday at least two passengers used stolen passports and said it was checking whether others aboard had used false identity documents.
The Taliban on Monday vowed to target Afghanistan's presidential election, urging their fighters to attack polling staff, voters and security forces before the April 5 vote to choose a successor to Hamid Karzai. Previous Afghan elections have been badly marred by violence, with at least 31 civilians and 26 soldiers and police killed on polling day alone in 2009 as the Islamist militants displayed their opposition to the US-backed polls. NATO combat troops will withdraw from the country by the end of 2014 after 13 years of fighting a fierce Islamist insurgency that erupted when the Taliban were ousted from power after the 9/11 attacks on the United States. "We have given orders to all our mujahideen to use all force at their disposal to disrupt these upcoming sham elections -- to target all workers, activists, callers, security apparatus and offices," the Taliban said in an emailed statement.