Azerbaijan has denied Iranian claims that Baku has been collaborating with Israel's spy services and helping assassins who killed Iranian nuclear scientists.
The Foreign Ministry rejected as "slander" a protest note given to its ambassador in Tehran, which complained about the alleged collaboration.
The note demanded that Azerbaijan prevent Israel's Mossad agency from carrying out anti-Iranian "activities" on its soil.
Ministry spokesman Elman Abdullayev told the AFP news agency that the Iranian complaint was in reaction to a protest last month from Baku to Tehran after two men with alleged links to Iranian intelligence were arrested on suspicion of plotting to kill prominent Israelis in Azerbaijan.
Azerbaijan's government maintains friendly ties with Israel, while its relationship with Iran has deteriorated in recent months amid accusations that Tehran has been sponsoring Islamic radicals in the country.
With agency reports