Ukraine, Belarus and Russia have marked 30 years since the Chernobyl atomic power station exploded, and paid tribute to hundreds of thousands of workers who fought to limit the impact of the world's worst nuclear accident.
Radioactive fallout still contaminates a swathe of territory spanning all three states, as a result of the blast that destroyed reactor four of the Chernobyl plant in the early hours of April 26th, 1986, when they were republics of the Soviet Union.
A combination of design faults and human error triggered a catastrophic meltdown during a test to see how the reactor would respond to a power failure, and the explosion spewed fallout around the plant and high into the atmosphere.
Hundreds of thousands of Soviet servicemen and workers were deployed to Chernobyl in a massive clean-up operation that only had a limited impact, given that an area the size of Luxembourg is still too dangerous for human habitation.
About 30 people died in the immediate aftermath of the accident, but debate still rages over its long-term health impact. The World Health Organisation recognises a "dramatic increase in thyroid cancer . . . among those exposed at a young age" to the fallout, and "some indication of increased leukaemia and cataract incidence among workers" in the clean-up operation.
Other groups, including Greenpeace, predict that tens of thousands of people will die as a result of health issues linked to radiation released by the disaster.
"The issue of the consequences of the catastrophe is not resolved," Ukrainian president Petro Poroshenko said during a memorial at the plant, which is about 100km north of Kiev and very close to the Belarusian border.
“They have been a heavy burden on the shoulders of the Ukrainian people and we are still a long way from overcoming them,” he added.
A vast €1.5 billion metal shelter is being constructed beside the plant, and next year it will be slid over the now-crumbling concrete “sarcophagus” that was quickly built around the ruined reactor to stop more radiation leaking out.
Some 40 countries, including Ireland, have contributed to the fund to build the new “shelter”, which will be the world’s largest moveable land-based structure.
“We honour those who lost their health and require special attention from the government and society,” said Mr Poroshenko, whose administration has been criticised in recent months for cutting benefits to some people from areas affected by the accident.
“It’s with an everlasting pain in our hearts that we remember those who lost their lives to fight nuclear death,” he added.
In Belarus, where some 470 towns and villages were permanently evacuated after the accident, President Alexander Lukashenko hailed his people's response and said international help had been "insignificant".
“Faced with a national disaster, the Belarusian people . . . showed true heroism,” he declared.
Russian president Vladimir Putin said the disaster's impact would have been far greater if not for the "courage and dedication of fire-fighters, servicemen, experts and medical workers who honourably performed their professional and civic duty".