Iran warns 'terrorists' near border in Karabakh fighting
"It is unacceptable for us that some people want to send terrorists from Syria and other places towards regions near our frontiers," President Hassan Rouhani said, quoted on state television.
Heavy fighting erupted on September 27 in one of the most combustible frozen conflicts left over from the collapse of the Soviet Union.
French President Emmanuel Macron said Ankara had sent Syrian "jihadists" to the region, accusing Turkey of crossing a "red line".
Turkey has not responded publicly.
Rouhani, which has good relations with both Yerevan and Baku, reiterated Wednesday that "occupation is in no case acceptable".
"Everyone" must "accept the reality... and respect other countries' territorial integrity", he said.
Rouhani at the same time condemned "those who, on one side or the other, pour oil on the fire", without naming Turkey which has declared open support for Azeri military action to reclaim the enclave.
On Saturday, Tehran warned against any "intrusion" after mortar fire hit Iranian villages along the border.
The Islamic republic is home to a large Azeri community, mainly in the northwest.
According to some estimates, Azeris make up 10 million of the 80-million population of Iran, which is also home to almost 100,000 Armenians.