Russia will help Iran build a second nuclear power plant, according to Tehran’s top nuclear official.

The head of Iran’s atomic energy organization announced the deal on Wednesday as lawmakers on Capitol Hill fought back against a White House bid to stop them from passing new sanctions on Iran.

“We hope to see the construction of the country’s second nuclear power station start” in March 2014 and be led “by the Russians,” Ali Akbar Salehi, head of the Iranian Atomic Energy Organization, announced on Tuesday, according to state-run media reports.