AFP published this article:

More than 50,000 protesters took to streets across Greece on Wednesday and workers staged mass strikes, expressing anger over the country's worst rail tragedy and urging the prime minister to resign.

At least 57 people were killed, and 14 others remain in hospital after a freight train crashed head-on with a passenger train, carrying mostly students, on February 28.

Demonstrators in Athens waved signs reading "it's not an accident, it's a crime" and "it could have been any of us on that train".

By early afternoon, police said up to 53,000 demonstrators had taken to the streets across the country to protest the accident.

"I am here to pay tribute to the dead but also to express my anger and my frustration," Athens protester Niki Siouta, a 54-year-old civil engineer, told AFP.

"This government must go."

There were about 30,000 protesters in Athens, 15,000 in Greece's second city Thessaloniki and 10,000 in the western port city of Patras, a police spokeswoman told AFP.

- Calls to resign -

Fourteen people were detained for questioning in the capital on suspicion of offences including carrying flares, she added.

Alongside the protesters, Greek civil servants staged a 24-hour walkout while doctors, teachers, bus drivers and ferry crew members also went on strike.

Railways were paralysed as train workers extended strike action launched in the aftermath of the accident.

Last week protests triggered by the crash saw riot police clash repeatedly with demonstrators, including in Athens. The public order ministry has said talks were held with protest organisers to avert new violence.

Calls are growing louder for Prime Minister Kyriakos Mitsotakis to quit over the tragedy, which has shone a harsh spotlight on decades of government mismanagement of the rail network.

A station master, who admitted forgetting to reroute one of the trains, has been arrested and charged, but the government has been criticised for seeking to shift the blame mainly on him.

Greece's transport minister resigned on March 1 and Mitsotakis has apologised to victims' families, pledged to get to the root of what happened and embarked on a flurry of public appearances in an apparent bid to soothe anger.

- 'Belated' -

The premier visited the crash site and gave a televised address, blaming "human error" for the accident while calling for a special committee of experts to investigate.

But critics have been merciless. Writing in liberal daily Kathimerini, columnist Pantelis Boukalas called the prime minister's apology "belated" and said that some may suspect it was "guided by PR gurus".

The prime minister and other politicians suspended election campaigning in the wake of the tragedy. There is now speculation that the polls, expected in April, could be delayed until May.

Mitsotakis has vowed to seek EU assistance to "finally" modernise the train network and called on the Supreme Court to investigate the tragedy as fast as possible.

There is little sign, however, that public anger is easing. Last weekend, football fans around the country hurled insults at the prime minister during matches.

Political life will resume Thursday after a period of national mourning, but the premier seems in no rush to confront the issue of the looming polls.

Asked Monday when Mitsotakis will set an election date, government spokesman Yiannis Economou replied: "At this stage, this issue is not on the prime minister's mind at all."