Azerbaijan in row with Iran over 'Israeli spies'
Azerbaijan has angrily denied an Iranian claim that it has been helping Israeli spies plotting against Iran.
Iran says agents of the Israeli secret service Mossad were behind recent killings of Iranian nuclear scientists.
The latest victim was Mostafa Ahmadi-Roshan, killed by a car bomb in north Tehran on 11 January.
Azerbaijan's foreign ministry called Iran's claim "slander". On Sunday Iran had summoned the Azeri ambassador and given him a protest note.
An Azeri foreign ministry spokesman, Elman Abdullayev, said the Iranian protest was an "absurd reaction" to Azerbaijan's protest last month over an alleged plot by Iranian agents to kill Israelis in Azerbaijan.
Energy-rich Azerbaijan, a mainly Muslim country, has a secular government and borders on Iran. Azerbaijan has friendly ties with Israel and the US, who accuse Tehran of trying to develop nuclear weapons.
Azeri-Iranian relations have long been strained over the large ethnic Azeri minority in northern Iran.'External interference'
The Iranian protest note to Azerbaijan on Sunday asked the Azeri government to "stop the activities of the Mossad intelligence services in that country against Iran", Iran's Irna news agency said.
Azeri ambassador Cavansir Akhundov was told that "some of the terrorists linked with the terror of Iranian scientists" had travelled to Azerbaijan and then on to Israel "for co-operation with the spying network of the Zionist regime", Irna reported.
The Azeri spokesman insisted on Monday that Azerbaijan "will not permit any external interference or any terrorist activity on its territory".
Iran refuses to negotiate over its uranium enrichment programme, which it says is purely civilian in nature.
Western countries have tightened sanctions against Iran, amid widespread suspicions that Tehran is trying to build nuclear weapons.
In November, the UN's International Atomic Energy Agency said it had information suggesting Iran had carried out tests "relevant to the development of a nuclear explosive device".