The funds will go toward securing the outer shell of the mothballed reactor to prevent leakage of radioactivity, the German environment ministry said.

"We must not leave Ukraine alone in coping with the consequences of this catastrophe. International aid is still indispensable," Environment Minister Sigmar Gabriel said in a statement.

Gabriel said Germany had also urged Russia to step up its investment in the Chernobyl Shelter Fund, managed by the London-based European Bank for Reconstruction and Development, noting that the clean-up is expected to cost more than one billion dollars.

"With the new sum, German contributions to the Fund since 1998 will reach 60.5 million euros," the ministry said, in addition to the 28 percent of the European Union's total contribution of 240 million euros provided by Berlin.

Chernobyl's number-four reactor, in what was then the Soviet Union and is now Ukraine, exploded on April 26, 1986, sending a radioactive cloud across Europe.

The power station was completely shut down on December 15, 2000.