An underground nuclear power plant in Iran will achieve full generation capacity in early February, Iranian newspaper Kayhan quoted the country’s atomic chief as saying.

The news is likely to further increase tensions between Iran and the West over the country’s clandestine nuclear research. Western nations suspect Iran of pursuing a secret weapons program while Tehran says it needs nuclear research for peaceful energy purposes. Negotiations have been stalled for 12 months.

“The Fordow nuclear enrichment plant will be operational in the near future ... 20 per cent, 3.5 per cent and four per cent enriched uranium can be produced at this site,” said Fereydoun Abbasi Davani, the head of Iran's Atomic Energy Organisation, the Kayhan daily reported on Sunday.

Fordow is located deep inside the mountains in central Iran.

Iran has been facing sanctions from the UN Security Council over its refusal to abandon uranium enrichment. The U.S. and the EU have also imposed unilateral sanctions against Iran.