Putin arrives in Iran for first trip outside former Soviet Union since his invasion of Ukraine

(CNN)Russian President Vladimir Putin arrived in Iran on Tuesday for his first international trip beyond the borders of the former Soviet Union since launching his invasion of Ukraine, which effectively ruptured ties with the West.

Putin met with Iranian President Ebrahim Raisi in Tehran, and was scheduled to hold discussions with Turkish President Recep Tayyip Erdogan. He also met with Iran's Supreme Leader Ayatollah Khamenei on Tuesday, according to Iranian state news agency IRNA.

"I am very pleased to be on the hospitable Iranian soil...We can boast about record figures in terms of trade growth," said Putin in a bilateral meeting with Raisi.

"We are strengthening our cooperation on international security issues, making a significant contribution to the settlement of the Syrian conflict."

Raisi also hailed a "significant" commitment to security cooperation between the two countries.

"There has been good experience of the two countries in fighting terrorism, which I think has brought security to the region," he said.

Russia's relationship with Iran has alerted Western officials as he prepares to ramp up ground offensives in eastern Ukraine following his troops' capture of the Luhansk region.

Recently declassified US intelligence indicates that Iran is expected to supply Russia with "hundreds" of drones -- including weapons-capable drones -- for use in the war in Ukraine, with Iran preparing to begin training Russian forces on how to operate them as early as late July, according to White House officials.

"Russia turning to Iran for the help speaks volumes about the degree to which both nations, for their actions into different areas of the world, have been increasingly isolated by the international community," the National Security Council coordinator for strategic communications John Kirby told CNN last week.

Putin's trip to Iran will also see him meet face-to-face with Erdogan -- the leader of NATO member Turkey -- and comes after the Erdogan repeated his threat to block the ascension of Sweden and Finland to the alliance after conditionally agreeing to green light their bid in June.

"I would like to remind you once again that we will freeze the process if they do not take the necessary steps to fulfill our conditions," Erdogan said Monday after a cabinet meeting. He lifted his opposition to the expansion at a NATO summit last month -- a major diplomatic breakthrough that provided a blow to Putin.