The armed men broke onto the runway of the Mother Theresa airport on Tuesday afternoon and stole the cash destined for a bank in Vienna on an Austrian Airlines flight.

The family of Admir Murataj, killed in a gunfight with the police, identified his body on Wednesday, local media reported.

Investigators say he was among four men who used a firefighters' entry to access the runway.

They were in a stolen van bearing the logo of the tax authorities and carrying false license plates.

According to the initial investigation passengers were already aboard the Austrian Airlines flight when the group arrived on the runway.

Heavily armed robbers, wearing masks and dressed in military fatigues carried out the heist in less than five minutes.

Police did not reveal the exact amount of stolen money, but Albanian media put it at between 2.5 million and 10 million euros ($2.8 and 11.3 million).

Foreign banks operating in Albania send their hard currency to Vienna because Albania's central bank does not accept such deposits for security reasons.

Murataj, armed with an automatic rifle and a grenade, was killed in a shootout with the police on a nearby road.

The other gunmen managed to flee despite the deployment of special police backed by two helicopters.

The dead man's brother Cen Murataj, speaking to Albanian reporters outside a morgue where he arrived to identify his body, doubted whether he was the ringleader "since an organiser could not have been killed".

But Murataj was already known by police in the region.

In 2013 he fled a Greek prison along with about 10 other Albanian inmates, media reports said.

He was also the prime suspect in a robbery of a money transporter on the Tirana airport road in 2016.

That was one of a string of heists on the road.

In February 2017, robbers made off with 3.2 million euros, in June 2016 about 995,000 euros, while last year there were two similar attacks.

On Wednesday, criticism grew over security measures at the airport, notably since the robbery coincided with a visit by Matthew Palmer, a high-ranking US official.

Investigators said the robbers were apparently very well informed and may have had accomplices at the airport.

They questioned dozens of staff members, notably security services employees.

The opposition to socialist Prime Minister Edi Rama said the government had displayed "baffling incompetence".

"They are very competent to crack down on the opposition protesters with tear gas and batons of hundreds of policemen, but not to secure the country's only airport," said Gazmend Bardhi, a top official of the Democratic Party.

"Security measures within the airport have completely failed," Spiro Brumbulli of the association of Albanian banks told AFP, noting that the security is handled by a private Chinese company.

"It is a very serious affair and unfortunately not the first one," said Infrastructures Minister Belinda Balluku.

She regretted that the Chinese company had rebuffed government requests for stepped-up investment in security.

The airport is "very vulnerable" to such attacks, the minister said.

An Austrian Airlines spokeswoman earlier insisted the crew and passengers had not been in any danger but said that as a security measure there would be no further cash transfers from Tirana to Vienna.