A German tourist has been detained in Iran, the German foreign ministry said on Saturday, declining to give further details beyond saying the man was receiving consular assistance.

The Iranian interior ministry was not immediately available to comment on the detention.

News of the arrest follows the detention of a string of foreigners and dual nationals by Iran's security forces over recent years, mostly on espionage and security-related charges. Rights groups call that a tactic to win concessions from abroad by inventing charges, which Tehran denies.

In June, an Iranian appeals court confirmed a sentence of nearly nine years for jailed French tourist Benjamin Briere on spying charges, about two years after he was arrested near the border with Turkmenistan for taking pictures with a drone.

In July, Iran said it had arrested a Swedish citizen on espionage charges, weeks after a court in Stockholm sentenced a former Iranian official for war crimes.

An Iranian court is currently trying Jamshid Sharmahd, a German-Iranian charged with leading an armed opposition group. Tehran said in 2020 its intelligence services had detained U.S.-based Sharmahd without giving details. His family said he had been abducted while visiting Dubai.

Last August, an Iranian court sentenced German-Iranian rights activist Nahid Taghavi to more than 10 years in prison on national security charges.