MOSCOW - The presidents of Russia and Iran have held talks that Vladimir Putin's spokesman says covered military and nuclear co-operation, as well as the fight against the Islamic State group.

Putin and Iran's Hassan Rouhani met Thursday in the Russian city Ufa, which is hosting a summit of the Shanghai Cooperation Organization in which Iran has observer status.

The Russian president's spokesman, Dmitry Peskov, said Putin noted "positive dynamics" in the ongoing Vienna talks about a final agreement on Iran's nuclear program, according to Russian news agencies.

Peskov declined to say whether the talks touched on the delivery of S-300 advanced air-defence systems to Iran. After a framework agreement on Iran's nuclear program was reached this spring, Putin lifted Russia's suspension on sending the S-300s, but no deliveries have been reported.