Iran on Sunday accused its neighbour Azerbaijan of collaborating with Israel's spy services and facilitating the assassins who have killed Iranian nuclear scientists in recent years.

The foreign ministry summoned Azerbaijan's ambassador in Tehran, Javanshir Akhundov, to protest against the alleged collaboration and demand that Baku prevent Mossad from carrying out anti-Tehran "activities" on its soil.

"Some of the terrorists linked to the assassination of Iranian nuclear scientists have travelled to Azerbaijan... (where they are) facilitated to travel to Tel Aviv," the official IRNA news agency website said, quoting the ministry.

The Islamic republic has repeatedly accused its arch-foes Israel and the United States of masterminding the assassination of five of its scientists in recent years.

Israel, widely seen as the prime suspect in the killings, neither denied nor confirmed involvement.

Relations between Tehran and Baku have taken a turn for the worse in recent months. In January, Azerbaijan said it had detained two people allegedly linked to Iranian intelligence accused of plotting attacks.

And in October 2011, Iran accused its northwestern neighbour's security forces of shooting dead an Iranian border guard who had strayed into Azerbaijan.