The truck, which had been traveling from Hungary to Austria, was found on Thursday on an Autobahn near the borders with Slovakia and Hungary.

Austrian newspaper "Krone" reported on Friday that three people had ben arrested in Hungary in relation to the deceased migrants.

Authorities in the eastern Austrian state of Burgenland were due to announce the exact number of dead late on Friday morning.

"Work continued throughout the night, but I expect all the bodies have been removed now," said Helmut Marban, a police spokesman for the Burgenland province.

"Forensic investigators are still at the lorry and trying to establish all the facts."

Abandoned truck

The vehicle found on Thursday had the markings of a Slovakian poultry company but Hungarian license plates. Officers stopped to approach the truck after they noticed it parked up for a long period and thought it had mechanical trouble.

As they approached the vehicle, officers noticed "blood dripping" from the vehicle as well as "the smell of dead bodies." The van driver was nowhere to be seen.

Police said in a press conference on Thursday that the migrants, who were traveling in the truck, may have died before they entered Austria on Wednesday evening.

EU migrant crisis

Thursday's discovery was just one in string of tragedies to hit migrants as the European Union grapples with unprecedented waves of refugees fleeing violence in the Middle East and Africa.

German Chancellor Angela Merkel, who was in Austria on Thursday for a summit with Balkan leaders on Europe's migrant crisis, said she was "shaken" by the "horrible" news.

"This is a warning to us to tackle this migrants issue quickly and in a European spirit, which means in a spirit of solidarity, and to find solutions," Merkel said.

ksb/msh (AFP, Reuters)