Greek prosecutors on Thursday charged three more railway officials in connection with the country's worst train crash that killed 57 people, as the prime minister vowed "absolute transparency" in the probe into the tragedy.
Public anger has soared since the February 28 head-on collision in central Greece, with tens of thousands demonstrating nationwide on Wednesday.
The stationmaster on duty at the time of the accident, who allegedly directed both trains onto the same track by mistake, was charged several days ago.
On Thursday, a rail supervisor responsible for staff rotas - who allegedly put the inexperienced stationmaster on night duty during a busy holiday period - was charged, a judicial source told AFP.
Two other stationmasters, who allegedly left work early, were also charged. All three face counts of negligent manslaughter, causing bodily harm and transport disruption and could face life in prison if convicted.
With anger growing at long-running mismanagement of the rail network, Prime Minister Kyriakos Mitsotakis opened his first cabinet meeting since the crash by vowing "absolute transparency in the investigation to uncover errors".
The conservative leader, who is expected to run for re-election in the coming months, also promised "immediate actions to improve the problematic situation in the railways".
He vowed to "move heaven and Earth" to ensure improvements to safety systems were completed.
"We are all responsible for this, we must be brave enough to admit it," said Mitsotakis in televised remarks.
On Wednesday, huge crowds took to the streets in the biggest protests yet since the crash, calling for justice for the victims and for the government to resign.
Mass protests
They waved banners that read "It's not an accident, it's a crime" and "It could have been any of us on that train" as clashes erupted in Athens and Greece's second city Thessaloniki.
Greek civil servants staged a 24-hour walkout while doctors, teachers and transport workers also went on strike on Wednesday.
Calls have grown for Mitsotakis to quit over the tragedy.
The initial blame on the stationmaster stoked public anger, with some seeing it as a bid to deflect attention from chronic underfunding and mismanagement of the railways.
In his remarks Thursday, the prime minister apologised again and said that "we... must not hide behind a series of human errors".
The cabinet meeting was the first since the accident and a period of national mourning.
Later Thursday, a religious ceremony will take place at the crash site in memory of the victims.
Greece's transport minister resigned following the crash, and Mitsotakis has been scrambling to limit the political fallout and soothe public anger.
He has pledged to work with the European Union to modernise the country's railway network, and on Wednesday met visiting EU officials to get their advice.
The prime minister and other politicians suspended campaigning for upcoming elections in the wake of the tragedy. There is now speculation that the polls, initially expected in April, could be delayed until May.