A donor conference set up to raise money to make the Chernobyl nuclear disaster site safe has fallen short of its goal.
The Ukrainian government says pledges at the gathering in Kiev total 550 million euros. The target is 740 million.
There are plans to build a new shell to cover the reactor that exploded in 1986.
The EU has pledged an extra 110 million euros. Officials are optimistic the remaining funds can be found.
The crisis at Fukushima in Japan has made the event particularly relevant.
“This is a moment for deep reflection,” said UN Secretary General Ban Ki-moon, attending the conference. “How do we ensure both the peaceful uses of nuclear energy and maximum safety? We need a global rethink on this fundamental question.”
As the 25th anniversary of the accident approaches, the Chernobyl museum near Kiev has been receiving a growing number of visitors, mainly schoolchildren.
An area with a 30 kilometre-radius around the plant remains largely uninhabited.
One UN expert has said the health risks in the fallout-affected areas are much smaller now than they were 15 or 20 years ago.
Related: Chernobyl’s steel arch shelter