Iran said it has executed a man caught working as a spy for Israel’s Mossad intelligence agency, accusing him of passing on secrets—including information about an Iranian nuclear scientist who was killed in Israel’s recent attacks.

Newsweek has contacted the Israeli Foreign Ministry for comment.

The reported execution reflects Iran’s intensifying efforts to root out suspected espionage following the “12-day war” in June, which saw Israel and the U.S. strike Iranian nuclear facilities. Amir Hatami, the commander in chief of Iran’s military, warned on Sunday that threats from Israel persisted and that Iranian forces “were ready for operations,” Iranian state media reported.

Iran executed three men charged with spying for Israel on June 24 as part of a sweeping crackdown. Human rights groups have condemned a wave of hundreds of arrests and warned that the government is using the June conflict as a pretext to escalate repression. Rights groups have also cited concerns over forced confessions.

The Iranian news agency SNN, or Student News Network, reported that a man named Roozbeh Vadi had been found guilty of “espionage and intelligence cooperation in favor of the Zionist regime” and hanged on August 5.

The news agency did not elaborate on which organization Vadi worked for but said he had traveled to Vienna five times, including for training, where he met Mossad agents.

In the course of his “extensive cooperation with the Zionist regime,” the man “provided information to the Mossad spy service about one of our country’s nuclear scientists who was martyred in the recent Israeli aggression,” SNN reported.

Israel targeted and killed several prominent Iranian military figures and nuclear scientists in its strikes in June, the Israel Defense Forces and Iranian media reported.

Vadi had been placed under surveillance after he returned from one of his trips abroad and was arrested “when his connections and cooperation with the Zionist enemy were discovered,” SNN said.

Amir Hatami, the commander in chief of Iran’s military, said of Israel on Sunday, as reported by the IRNA news agency: “A 1 percent threat must be perceived as a 100 percent threat. We should not underestimate the enemy and consider its threats as over.”

U.S. President Donald Trump said on July 28: “We wiped out their nuclear possibilities. They can start again. If they do, we’ll wipe it out faster than you can wave your finger at it. We will do that gladly, openly and gladly.”

There would appear to be little prospect of an easing of tension between Iran and Israel, especially in the absence of a diplomatic breakthrough in nuclear talks between Iran and European parties to the 2015 Iran nuclear deal.