The trial of 11 men indicted in the case of 71 migrants who died in the back of a refrigerated lorry in 2015 has started in Hungary.
Prosecutors have asked for life sentences for the four alleged people smugglers, who are facing murder charges.
The other defendants are facing shorter prison terms and expulsion from Hungary.
Migrants from Syria, Iraq and Afghanistan were among those who suffocated in the back of a refrigerated lorry with Hungarian licence plates which was abandoned in the emergency lane of the A4 motorway near Parndorf, Austria, near the Hungarian border, on August 27 2015.
The victims, who died while the lorry was still in Hungary, included 59 men, eight women and four children.
Ten of the 11 defendants were present at the court in Kecskemet, the central Hungarian city where the alleged smugglers purchased the lorry and began their journey to Hungary's border with Serbia to pick up the migrants.
One defendant is a fugitive being tried in absentia.
The migrants were packed into the lorry near the village of Morahalom before heading towards Austria.
"Approximately half an hour after the departure, the migrants indicated with bangs and cries that they were running out of oxygen," prosecutors said ahead of the trial, adding that the driver was told to ignore their pleas by his Bulgarian boss.
"As a result, the 71 victims locked in the load area suffocated in horrendous conditions three hours after the departure," while still in Hungary, they said.
The defendants include nine Bulgarians, one Bulgarian-Lebanese and one Afghan.
They allegedly smuggled some 1,200 people from the Hungary-Serbia border to Austria or Germany in 2015.
At least some 400,000 migrants passed through Hungary in 2015, nearly all on their way to Germany and other destinations in western Europe.
The flow of people ebbed considerably after September 2015, when Hungary built razor-wire fences on its southern borders with Serbia and Croatia.
