GENEVA (Reuters) - A U.S. citizen held in Iran has been sentenced for an unspecified crime, Iranian news agencies reported on Monday, in a case likely to worsen already terrible relations with the United States.

Michael White, a 46-year old U.S. Navy veteran, was arrested last July while visiting his Iranian girlfriend, the New York Times has reported. The arrest - the only known one of a U.S. citizen since President Donald Trump took office - was confirmed by Iran only in January.

On Monday, the prosecutor in the northeastern city of Mashhad, Gholamali Sadeqi, said White had been sentenced, the Fars news agency reported.

He said White had been accused of a security-related charge but did not specify if that was what he had been convicted of. Iranian officials have never said why he was being held.

Trump withdrew from an international agreement on Iran’s nuclear program and re-imposed crippling economic sanctions last year. He warned in 2017 Tehran would face “new and serious consequences” unless all unjustly held U.S. citizens were freed.

White’s sentencing comes days after Iran appointed a new head of the judiciary - Ebrahim Raisi, a hardline cleric who is a protégé of Supreme Leader Ayatollah Ali Khamenei. The appointment is seen as weakening the political influence of President Hassan Rouhani, a relative moderate.

Also on Monday, an Iranian court handed a new sentence to renowned human rights lawyer Nasrin Sotoudeh which her husband said was 38 years in prison and 148 lashes. The official Islamic Republic News Agency said she had been sentenced to seven years.