Mr Putin met Iranian supreme leader Ayatollah Ali Khamenei, Iranian President Ebrahim Raisi and Turkish President Recep Tayyip Erdogan on Tuesday as Moscow shelled eastern and southern Ukraine.
The trip shows how isolated Russia has become, said White House national security spokesman John Kirby.
The leaders discussed a deal that would resume Ukraine’s Black Sea grain exports, now blockaded by Russia.
Mr Putin said that Moscow would only ease the path for Ukrainian grain exports if the West lifts sanctions on Russian shipments.
Not all issues have been resolved on the matter of grain shipments “but the fact that there is movement is already good”, he said.
After talks with Mr Erdogan and Mr Raisi, Mr Putin told reporters that any deal hinged on the West's willingness to yield some ground.
“We will facilitate the export of Ukrainian grain but we are proceeding from the fact that all restrictions related to air deliveries for the export of Russian grain will be lifted,” he said.
The UN Food and Agriculture Organisation recently said that about 18 million tonnes of grain was stranded at silos in Ukraine's ports, unable to transit the Black Sea to global markets. Ukrainian farmers are trying to harvest another 60 million tonnes in the current season, but fighting is raging across much of the east of the country, its agricultural heartland.
It was Mr Putin’s first in-person meeting with a Nato leader since Russian troops invaded Ukraine in late February, as well as a pointed message to the West about Russian plans to forge closer strategic ties with Iran, China and India to offset the impact of western sanctions.
The meeting between Mr Putin and leaders from the region comes a few days after US President Joe Biden visited Israel and Saudi Arabia.
Russian and Ukrainian delegations are due to meet on Wednesday in Istanbul, alongside Turkish and UN representatives, amid rising hopes for an accord.
The EU's foreign policy chief Josep Borrell warned this week that the grain impasse was “an issue of life and death for many human beings”.
Mr Erdogan also pressed Turkey's case for a military offensive against Syria’s Kurds, despite Iran's caution against such a move.
The Turkish president said he expected the full support of Tehran and Moscow in Ankara’s fight against “terrorists” in Syria.
Ankara has long maintained that a US-backed Kurdish militia force, the Syrian Democratic Forces and their related People's Protection Units, are a terrorist organisation linked to the Kurdistan Workers' Party (PKK).
The PKK, who are also listed as a terror group by the US and EU, have fought a bloody, four decade long insurgency with the aim of forming an autonomous Kurdish region in Turkey.
But Syrian President Bashar Al Assad has been staunchly opposed to Turkish incursions into his country, which have involved Ankara arming and funding former Syrian rebel groups and sending military advisors, in between Turkish ground operations. Turkish-backed forces now occupy parts of several northern Syrian governorates, including Aleppo and Idlib.
Syrian and Turkish forces were involved in a number of ferocious clashes in early 2018 after an exchange of fire escalated.
The meeting between the leaders also discussed ways to end the Syria war. Iran and Russia have supported the government of Syrian President Bashar Al Assad while Turkey had backed rebel forces against the regime.
However, Ankara is also deeply opposed to a semiautonomous Kurdish administration in Syria’s oil-rich north-east. Lately, Mr Erdogan has repeatedly vowed to launch an offensive against Kurdish militants, on the back of a 2019 onslaught.
He accuses outlawed Kurdish militants of using the border region as a staging post for their decades-long insurgency against Turkey.
“What we expect from Russia and Iran is their support for Turkey in its fight against terrorism,” he said in televised remarks.