Tehran, Iran ? The head of Iran’s nuclear agency ruled out a compromise proposal to enrich uranium for his country’s controversial nuclear program in Russia, saying Saturday the process must be done in Iran.

The United States and European negotiators reportedly were willing to accept the compromise to allow Iran to move ahead with its nuclear program while ensuring it does not produce atomic bombs. Enrichment can produce material either for a bomb or for nuclear reactor fuel.

Vice President Gholamreza Aghazadeh, who also leads the country’s nuclear agency, said Iran was open to other proposals, referring to an earlier Iranian idea that other countries participate in the enrichment process on Iranian soil as a guarantee the program is used only for peaceful purposes.

“What is important for us is that we be entrusted to carry out enrichment in Iran. As for participation by other countries in Iran’s uranium enrichment program, we will consider it if there is any proposals,” he said.

But, when asked if Tehran would agree to carrying out enrichment abroad, Aghazadeh said, “Iran’s nuclear fuel will be produced inside Iran.”