NEW YORK - US prosecutors said in a court filing on Friday that a former consultant to Iran's mission to the United Nations recruited a United States-based atomic scientist to meet with Iranian officials about Iran's nuclear program.The filing regarding the former consultant, Ahmad Sheikhzadeh, does not contain criminal charges, but was made to support prosecutors' request for a tough prison sentence for him for tax fraud and conspiracy to violate sanctions against Iran.Sheikhzadeh pleaded guilty last November to the charges, which do not involve the Iranian nuclear program.In the filing, prosecutors said that, starting around 2005, Sheikhzadeh helped arrange meetings between the scientist and Iran's current president, Hassan Rouhani, previously the country's chief negotiator on nuclear issues, and Foreign Minister Mohammad Javad Zarif, formerly Iran's permanent representative to the United Nations.Sheikhzadeh's lawyer, Steve Zissou, said on Friday, "The only goal Dr. Sheikhzadeh has ever had was to improve relations between the two countries so that they could both live in peace."A spokesman for Iran's mission to the United Nations did not immediately respond to a request for comment.Prosecutors did not name the scientist, who they said was an Iranian national who had worked at a US nuclear power plant.They said the scientist, working with Sheikhzadeh, provided advice to help Iran negotiate with other countries over its nuclear program. For example, they said, he gave an estimate of how many gas centrifuges - devices used in enriching uranium - Iran would need to accomplish its nuclear goals.The scientist also helped develop Iran's public messaging around the nuclear program, prosecutors said.Iran reached a deal with the United States and other nations in 2015 to limit its nuclear program in exchange for relief from international sanctions. US President Donald Trump has criticized the deal and in April ordered that it be reviewed.Federal guidelines call for a sentence of up to four years and nine months for the crimes Sheikhzadeh pleaded guilty to, but prosecutors on Friday said in their filing that his "brazen" conduct warranted more than that.Sheikhzadeh is scheduled to be sentenced on July 17 by US District Judge Pamela Chen in Brooklyn. Zissou asked in a letter filed with the court on Friday to postpone the sentencing in light of the new filing.Authorities originally charged that Sheikhzadeh under-reported his UN income on his personal tax returns. They also said he used his bank account to help US-based co-conspirators invest money in Iran, violating sanctions.