Kuala Lumpur International Airport's security meets strict international standards, a Malaysian official said on Monday amid reports of security lapses at the airport.
Pressed for answers on how two men with Asian features could have boarded the ill-fated Malaysia Airlines MH370 with European passports, Department of Civil Aviation director-general Azharuddin Abdul Rahman said he was waiting for a report by security investigators on this matter.
Malaysia's Home Minister Ahmad Zahid Hamidi on Sunday said the two passengers who used stolen European passports were of Asian appearance, criticising border officials who let them through.
"I am still perturbed. Can't these immigration officials think? Italian and Austrian but with Asian faces," he was quoted by state news agency Bernama as saying late on Sunday.
Mr Azharuddin declined to comment on whether there is heightened security in Malaysia's airport but maintained that security had been strict.
"We have a national civil aviation security programme we have to comply with. As DCA, we have done our audits on KLIA, following standards by transport security administration of the US and Australia," said Mr Azharuddin.
On the possibility of a hijack, he said: "This is not discounted. We're looking at every aspect of what could have happened to the aircraft."
Malaysia Airlines had removed all unaccompanied baggage on flight MH370 before it took off on Saturday morning, adhering to international aviation protocols, he said.
"Every check-in baggage has a tag on the boarding pass. This was done to make sure the correct bags were removed from the aircraft," he told a press conference as the search for the missing plane entered its third day.
He said reports that Vietnamese searchers found a part that looks like the inner part of an aircraft door have not been officially verified by the Vietnamese government.
He said the search teams had also dispatched sea craft to investigate debris spotted by air crews on Sunday.
"Parts that look like an airplane's tail but when we dispatched craft to the area made known to us, it was logs tied together that look like pontoons," Mr Azharuddin said.
He said searches were also still being carried out in the Strait of Malacca on the possibility of the aircraft making an air turn back after taking off from KLIA.
Oil samples from the South China Sea recovered by Malaysian Maritime Agency Agency were also being studied by the Chemistry Department, with no time given on when the analyses would be finished.
Search operations are still ongoing and currently involves 34 aircraft, 40 ships, and more than 100 men in operations that has passed 60 hours now.
Air search is being done from 7am to 7pm daily while sea-borne searches are conducted round the clock.
Flight MH370 to Beijng lost contact with Subang Air Traffic Control 50 minutes after departing KLIA at 12.41am on Saturday.
It was due to land in Beijing at 6.30am, and had enough fuel to fly till 8.30am. The plane did not issue a distress signal nor was there bad weather when it disappeared.
The flight was carrying a total number of 239 people - comprising 227 passengers (including 2 infants) and 12 crew members.
Passengers from 14 nations and Taiwan were on board, the majority being Chinese nationals and Malaysians. No Singaporean was on board.
Flight MH370 was operated on a Boeing 777-200 aircraft, a codeshare with China Southern Airlines.
Malaysia said the search would go on round the clock until a decision is made to call it off.
On Chinese family members wishing to come to Kuala Lumpur to be closer to investigations, MAS CEO Ahmad Jauhari Yahya said up to five next of kin of each passenger will be flown in and put up in KL hotels.
The first of the families from China have already arrived in KL on Monday morning.
Local Malaysian families are being housed in the Everly Hotel in Putrajaya, half an hour from KLIA.