An Iranian court has convicted two men on charges of spying for Israel and the UK on Friday, according to Iranian state media.
One of the men was sentenced to 10 years for passing on information to four separate British intelligence agents.
The British "spy" was "very active during the sanctions era, giving advice and collaborating with Britain in order to optimize the effects of sanctions," IRNA state media said, quoting Yadollah Movahed, the prosecutor of southern Kerman province.
Movahed said the unnamed man was "notoriously known for having contacts with the British foreign secret service."
The report came after Britain announced on Tuesday plans to reopen its embassy in Tehran, ending a three-year diplomatic freeze.
The other man reportedly transferred information to the Israeli embassy in Thailand and Turkey, according to Movahed. Thailand has repeatedly found itself at the center of a shadow-war between Iran and Israel, with Iranian agents repeatedly attempting to carry out assassinations and terrorist attacks against Israeli officials and tourists.
Neither of the convicted men were named, but both are believed to be Iranian citizens and were arrested in Kerman province. It is not known if they were provided with legal representation.
Relations between Iran and Britain were strained for decades and they eventually broke off diplomatic ties in November 2011. That month Britain shuttered its Tehran embassy after students stormed the compound during a protest against new sanctions targeting Iran's vital oil exports. Britain then ordered the closure of Iran's mission in London.
The two countries resumed diplomatic ties in February.
The convictions come just one day after a group of cyber activists were sentenced to prison terms ranging from one to 11 years, amid an ongoing crackdown on political dissent.
IRNA quoted Movahhed Thursday as saying that the men, who were all already serving prison sentences for political crimes, were given the additional sentences for planning to work with the foreign media and helping out opposition websites in Iran.