By Parisa Hafezi

ANKARA (Reuters) - Iran's judiciary has indicted three detained Iranian dual-nationals and a Lebanese citizen also held in the Islamic Republic, the judiciary's official news website Mizan said on Monday.

Several Iranian dual nationals from the United States, Britain, Canada and France have been detained in the past few months and are being kept behind bars on various charges, including espionage or collaborating with a hostile government.

"After the issuance of indictments, the cases against (British-Iranian) Nazanin Zaghari-Ratcliffe, (American-Iranian) Siamak Namazi, (Canadian-Iranian) Homa Hoodfar and (U.S.-Lebanese) Nizar Zekka ... have been referred to court for processing," the website quoted Tehran prosecutor Abbas Jafari Dolatabadi as saying.

He did not provide details about the charges brought against the four. Dolatabadi also did not say whether the court was a Revolutionary Court, which handles security-related cases.

A judiciary source told Reuters their cases had been referred to the court "within the past two weeks".

"But it does not mean that they will stand trial soon. Iran's judiciary is reviewing their cases very carefully," said the official, who asked not to be named because of the sensitivity of the matter.

Iran does not recognize dual nationality and treats detainees only as Iranian, depriving them of consular access.

Zaghari-Ratcliffe, 37, a program coordinator with the London-based charity Thomson Reuters Foundation, was detained in early April before boarding a flight back to Britain with her two-year-old daughter. Her British husband, Richard Ratcliffe, says their daughter has been put in the care of Zaghari-Ratcliffe's family in Iran.

In a statement emailed to Reuters on Monday, the Foundation said Zaghari-Ratcliffe "has yet not been given access to a lawyer".

"I expect the Iranian authorities to free Nazanin and to release the passport of her daughter Gabriella as soon as possible," said Monique Villa, Thomson Reuters Foundation CEO in the statement.

ACCUSATIONS

Iran's elite Revolutionary Guards Corps (IRGC) accused Zaghari-Ratcliffe in a statement published last month of trying to "overthrow" the government. Her husband has dismissed the accusation.

Dubai-based businessman Siamak Namazi, a dual U.S.-Iranian citizen, was detained by the IRGC last October while in Iran visiting his family.

Dolatabadi did not mention the case of Namazi's 80-year-old father, Baquer Namazi, another dual American-Iranian national who his family said was detained in February. The Iranian authorities have not confirmed the elder Namazi's detention.

The U.S. State Department said on Monday that a U.S. citizen and a U.S. legal resident, reported to have been indicted in Iran, were "unjustly detained" and should be released.

Hoodfar is the most recent dual national to be arrested in Iran. The IRGC detained the 65-year-old Canadian-Iranian scholar on June 6 in Tehran. She had traveled to Iran in February for personal reasons, but had also been continuing her academic research while in the country, her family said.

Iranian state media said in November that American-Lebanese IT expert Nizar Zekka had been detained in Iran, accusing him of having links to the U.S. military and intelligence agencies. Lebanese media reported that Zakka had disappeared on Sept. 18 after attending a conference in Tehran.

The Iranian judiciary has not commented on their cases or made the charges against them public. But Iran's judiciary spokesman said in January that most of the detained dual nationals were facing espionage charges.

In January, Iran released four Iranian-American dual nationals and an American in a prisoner swap negotiated between the United States and Iran coinciding with the implementation of a landmark nuclear deal with six major powers in 2015 aimed at curbing Tehran's nuclear program in return for the lifting of economic sanctions.

The United States also released seven Iranians, six of whom also had dual U.S. nationality.

(Additional reporting by Mohammad Zargham in Washington, Writing by Parisa Hafezi,; Editing by Ralph Boulton)