UN Secretary-General Ban Ki-moon on Thursday reaffirmed the UN readiness to "provide any additional assistance" to disaster-stricken Japan if requested, a UN readout said in New York.

The secretary-general, who is on his official visit to Guatemala, made the statement as he was speaking on the phone with the director general of the International Atomic Energy Agency ( IAEA), Yukiya Amano.

"The secretary-general reaffirmed the United Nations'readiness to provide any additional assistance if requested," the readout said.

During the phone conversation, the secretary-general received a detailed briefing on the situation at the Fukushima nuclear plants and the ongoing efforts by the Japanese authorities, the readout said.