DUBAI (Reuters) - There are several detained dual citizens in Iran, most of whom face espionage charges, the judiciary spokesman was quoted as saying on Sunday, although he did not give details of any individual cases.

The comments come after an Iranian-British former BBC journalist, Bahman Daroshafaei, was detained last week in Tehran. His family said on Saturday they had not been informed of any charges against him.

Iranian Foreign Minister Mohammad Javad Zarif said in London on Thursday that he did not know about the case.

Tehran released four Iranian-Americans on Jan. 16 in a prisoner swap deal with Washington, including Jason Rezaian, the Washington Post’s Tehran bureau chief who was arrested in July 2014 and accused of espionage.

“We have several dual citizens in jail. Their charges are mostly the same (as Rezaian’s),” the judiciary spokesman Gholamhossein Mohseni Ejei was quoted as saying by the Fars news agency.

Ejei said that no verdict had been reached on Rezaian’s espionage charges.

“It is still important to know what he and those related to him were doing in Iran. So their case is still open.”

The prisoner swap was announced as world powers, including the United States, implemented a landmark nuclear deal with Iran. In exchange for the release of five Americans from Iran, the White House offered clemency to seven Iranians who were convicted or facing trial in the United States.

Another Iranian-British citizen, Kamal Foroughi, remains in detention after being arrested in 2011 while working in Tehran as a business consultant.

Iranian-American businessman Siamak Namazi, who was detained by Iranian authorities in October while visiting relatives, is still in jail.