The European Union pledged about 20 million euros (22.5 million dollars) in additional funding for the Chernobyl containment effort on Monday, the eve of the worst-ever nuclear disaster's 30th anniversary.
"The European Union has been at the forefront of the international efforts to deal with the aftermath of the Chernobyl nuclear disaster," the EU's commissioner for international cooperation and development, Neven Mimica, said in a statement.
Environmentalists, however, say the current clean-up and containment efforts pale in comparison to what's needed, given the slapdash work used to contain the radiation following the 1986 disaster.
Ukrainian President Petro Poroshenko will mark the anniversary in a ceremony at the Chernobyl Nuclear Power Plant on Tuesday, his office said in a statement.
Representatives of the European Bank for Reconstruction and Development (EBRD) and 28 countries that have contributed funds for the decontamination will attend the ceremony, according to a statement on the Chernobyl Exclusion Zone's website.
The international community has contributed more than 2 billion euros to cleaning up and preventing further contamination at Chernobyl, the European Commission said in a statement.
That amount includes 730 million euros contributed by the European Commission, the statement said.
On April 26, 1986, a malfunction during a system test of the plant's Reactor Number 4 set off a series of explosions that sent thousands of tons of radioactive material into the atmosphere.
About 100,000 residents were evacuated from the surrounding area in what were then the Soviet republics of Ukraine and Belarus, while about 600,000 Soviet workers strove to decontaminate the territory and erect a "sarcophagus" of lead and concrete to contain the radiation within the damaged reactor.
The sarcophagus, which was built in a rush, was never intended as anything other than a temporary solution. A new steel-based structure, the "New Safe Confinement," is being built to better enclose the reactor.
The environmental activist organization Greenpeace, which is also planning a demonstration at the Chernobyl site, emphasized earlier this month that the containment effort is still in its early stages.
"Trying to deal with the Chernobyl disaster is like the labour of Sisyphus. It has to be done, but will not be finished for hundreds of years, if ever," Greenpeace nuclear expert Tobias Münchmeyer said in a statement.
Sisyphus was a figure from Greek mythology forced to repeatedly roll a rock up a mountain, only to see it roll back down the mountain once he was done, before being forced to start over.
The sarcophagus is a "crumbling shell" whose "deterioration is accelerated by moisture leaking through the cracks," the statement said.
"The international community must ensure there's adequate long-term support for the Ukraine to recover all nuclear waste from the station and store it properly," according to Greenpeace.
About 5 million people still live in areas contaminated by the disaster, in Ukraine, Belarus and Russia, the environmental organization said.
However, despite the contamination surrounding the plant, the Chernobyl Exclusion Zone has de facto become one of the world's biggest nature reserves, as the lack of humans in the area has enabled animal populations to thrive, The Telegraph newspaper reported Sunday.
Radiation increases potential risk to animals, whereas humans present a more immediate risk by taking over habitats and hunting, the British newspaper quoted wildlife expert Nick Beresford as saying.