Russian President Vladimir Putin visited Tehran on Tuesday for talks with Iranian Supreme Leader Ayatollah Ali Khamenei, the Kremlin leader's first trip outside his country since Moscow launched a "special military operation" against Ukraine in late February.

Earlier on the same day, the National Iranian Oil Company (NIOC) and Russian gas producer Gazprom (GAZP.MM) signed a $40 billion primary deal for energy, according to Iran's oil ministry's news agency Shana.

"The contact with Khamenei is very important," Yuri Ushakov, Putin's foreign policy adviser, told reporters in Moscow. "A trusting dialogue has developed between them on the most important issues on the bilateral and international agenda."

In Tehran, Putin will also hold a face-to-face meeting with President of Türkiye, Recep Tayyip Erdogan, to discuss a deal aimed at allowing the resumption of Ukraine's Black Sea grain exports.

High on the agenda in Tuesday's trilateral talks that will also include Türkiye will be efforts to reduce violence in Syria, where Erdogan has threatened to launch more military operations to extend 30-km deep "safe zones" along the border. Moscow and Tehran both oppose any such action by Ankara.

"Maintaining the territorial integrity of Syria is very important, and any military attack in northern Syria will definitely harm Türkiye, Syria and the entire region and benefit terrorists," Khamenei told Erdogan, Iran's state TV reported.

Ahead of Putin's arrival, Mohsen Khojasteh-Mehr, CEO of the National Iranian Oil Company, and Vitaly Markelov, deputy chairman of the Management Committee of Russia's Gazprom, signed a $40 billion investment in Iran's petroleum industry, Shana reported.

The development of Iran's Kish and North Pars gas fields, as well as six oilfields, boosting pressure in the South Pars Gas Field, completion of LNG projects, swap of gas and petroleum products and construction of gas transfer pipelines, are among the most important highlights of the memorandum, according to the report.

Khojasteh-Mehr also said the substantial Russian investment in Iran's oil industry indicates the two countries' commitment to ensuring sustainable energy supply.

(With input from agencies)

(Cover: Russian President Vladimir Putin chairs a meeting with members of the government via video link at the Kremlin in Moscow, Russia, July 8, 2022. /Reuters)