Malaysian authorities have released security video of the two men who used stolen passports to board the Malaysia Airlines plane that vanished over the South China Sea.
The video has been released to international security agencies and will soon be released publicly.
As a massive search operation by nine countries has doubled to include remote parts of mainland Malaysia, police in Kuala Lumpur say they have identified one of the men who have emerged as a key focus of the investigation into the cause of the plane's disappearance.
Authorities in Kuala Lumpur have ruled out any lapses in security at Kuala Lumpur International Airport before the ill-fated early morning flight departed for Beijing last Saturday.
This has swung greater attention on to the behaviour of the two men travelling on passports stolen in Thailand, and their links to a shadowy Iranian intermediary who helped them book their flights through a travel agency in the seedy seaside Thai city of Pattaya.
Malaysia's acting transport minister Hishammuddin Hussein defended authorities for not releasing CCTV footage of the men earlier so their identities could more quickly uncovered by world-wide exposure.
"I do not want to affect the on-going investigation," Hishammuddin said.
"Our main focus is to find the aircraft and we do not want to be distracted."
The men's travel tickets were arranged through an Iranian man known as Ali who formerly lived in Pattaya and opened a restaurant there but is now believed to be living in Tehran.
Pattaya is a known haunt of international criminal networks where there is a thriving racket in stolen and forged passports.
Officials in Kuala Lumpur with knowledge of the investigation into the disappearance say there is growing concern about the failure to find any debris from the plane, fuelling speculation an explosion occurred on the Boeing 777, either from an explosive device or a technical fault.
But officials say until wreckage is found no possibility can be excluded, including a hijacking.
The plane appeared on radar to turn back towards Malaysia before it disappeared.
The pilots inexplicably made no distress call.
Malaysia Airlines insisted on Monday the plane's cockpit would have remained locked in compliance with international safety standards with only the pilots able to open it.
Airline security experts say that if an explosion caused the plane to crash it would probably have been smuggled into cargo and either detonated remotely or with a timer.
Meanwhile Malaysian officials have appealed for people not to spread rumours about the cause of the flight's disappearance, saying they are disrupting investigations and causing grief to relatives of the victims.
After meeting a delegation from the Chinese government on Monday officials backed away from earlier statements that the two passengers travelling on stolen passports were "Asian looking".
They also played down reports from China the men had links to the Chinese Martys' Brigade, a previously unheard of group that had reportedly claimed responsibility in a statement to some Chinese journalists.
Chinese media outlets have dismissed the claim as a hoax but it was circulated widely in social media.