And while Putin delivered smiling support to Iranian President Mahmoud Ahmadinejad, he kept the president's nuclear ambitions at arm's length, reports CBS News correspondent Richard Roth.
At a summit of the five nations that border the inland Caspian Sea, Putin said none of the nations' territory should be used by any outside countries for use of military force against any nation in the region. It was a clear reference to long-standing rumors that the U.S. was planning to use Azerbaijan, a former Soviet republic, as a staging ground for any possible military action against Iran.
"We are saying that no Caspian nation should offer its territory to third powers for use of force or military aggression against any Caspian state," Putin said.
Ahmadinejad also underlined the need to keep outsiders away from the Caspian.
"All Caspian nations agree on the main issue - that all aspects related to this sea must be settled exclusively by littoral nations," he said. "The Caspian Sea is an inland sea and it only belongs to the Caspian states, therefore only they are entitled to have their ships and military forces here."
Putin, whose trip to Tehran is the first by a Kremlin leader since World War II, warned that energy pipeline projects crossing the Caspian could only be implemented if all five nations that border the Caspian support them.
Putin did not name any specific country, but his statement underlined Moscow's strong opposition to U.S.-backed efforts to build pipelines to deliver hydrocarbons to the West bypassing Russia.
"Projects that may inflict serious environmental damage to the region cannot be implemented without prior discussion by all five Caspian nations," he said.
Other nations bordering the Caspian Sea and in attendance at the summit are: Kazakhstan, Turkmenistan and Azerbaijan.
CBS News producer Sia Zand in Tehran reports the low key summit was lent credence in the world of global politics by Putin's presence.
The Russian president's most internationally significant statement, reports Zand was his implicit, repeated support for Iran's nuclear program. Answering a question from a Russian journalist, Putin stressed the right of all countries in the region to pursue peaceful atomic programs under the guidelines set by the U.N. nuclear watchdog.
Putin, however, refused to set a date Tuesday for the start-up of Iran's first nuclear power plant, but stressed that Moscow would not back out of its commitment to complete the project.
After talks with Ahmadinejad, Putin said revisions to the $1 billion contract to build the plant in the Iranian port of Bushehr are necessary to clarify certain legal aspects and financial obligations by each side.
At the same time, he said, "We are not going to renounce our obligations."
The plant is leverage Moscow can use against Iran's renegade efforts to enrich uranium, potentially on the way to developing nuclear weapons, reports Roth.
Putin's careful stance suggested that Russia is seeking to preserve solid ties with Iran without angering the West. A clear pledge by Putin to quickly finish the plant would embolden Iran and could complicate international talks on the standoff over Iran's nuclear program.
On Monday, U.S. Defense Secretary Robert Gates said the United States alone cannot force Iran to give up its nuclear ambitions.
"Our allies must work together on robust, far-reaching and strongly enforced economic sanctions. We must exert pressure in the diplomatic and political arenas as well. And, as President Bush has said, with this regime we must also keep all options on the table," Gates said.
Last week, Putin bluntly spelled out his disagreements with Washington, saying that he saw no "objective data" to prove Western claims that Iran is seeking nuclear weapons. Though Russia has shielded Iran from harsher sanctions in the U.N. Security Council, its relations with Tehran have been hurt by disputes over the $1 billion deal to build the nuclear plant.
"Threatening someone, in this case the Iranian leadership and Iranian people, will lead nowhere," Putin said Monday during his trip to Germany. "They are not afraid, believe me."
Iran's rejection of the council's demand and its previous clandestine atomic work has fed suspicions in the U.S. and other countries that Tehran is working to enrich uranium to a purity usable in nuclear weapons. Iran insists it is only wants lesser-enriched uranium to fuel nuclear reactors that would generate electricity.
Putin's visit to Tehran is being closely watched for any possible shifts in Russia's carefully hedged stance in the nuclear standoff.
Putin emphasized Monday that he would negotiate in Tehran on behalf of the five permanent U.N. Security Council members - United States, Russia, China, Britain and France - and Germany, a group that has led efforts to resolve the stalemate with Tehran.
In Washington, State Department spokesman Tom Casey said the U.S. government expected Putin to "convey the concerns shared by all of us about the failure of Iran to comply with the international community's requirements concerning its nuclear program."
Putin's schedule also called for meetings with Ahmadinejad and the Iran's Supreme Leader Ali Khamenei.
While the Kremlin has shielded Tehran from a U.S. push for a third round of U.N. sanctions, Iran has voiced annoyance about Moscow's foot-dragging in building a nuclear power plant in the southern port of Bushehr under a $1 billion contract.
Russia warned early this year that the plant would not be launched this fall as planned because Iran was slow in making payments. Iranian officials have angrily denied any payment arrears and accused the Kremlin of caving in to Western pressure.
Moscow also has ignored Iranian demands to ship fuel for the plant, saying it would be delivered only six months before the Bushehr plant goes on line. The launch date has been delayed indefinitely amid the payment dispute.
The legal status of the Caspian - believed to contain the world's third-largest energy reserves - has been in limbo since the 1991 Soviet collapse, leading to tension and conflicting claims to seabed oil deposits.
Iran, which shared the Caspian's resources equally with the Soviet Union, insists that each coastal nation receive an equal portion of the seabed. Russia, Azerbaijan and Kazakhstan want the division based on the length of each nation's shoreline, which would give Iran a smaller share.
Putin's visit took place despite warnings of a possible assassination plot and amid hopes that a round of personal diplomacy could help offer a solution to an international standoff on Iran's nuclear program.
Putin's trip was thrown into doubt when the Kremlin said Sunday that he had been informed by Russian intelligence services that suicide attackers might try to kill him in Tehran, but he shrugged off the warning.
Iranian Foreign Ministry spokesman Mohammad Ali Hosseini dismissed reports about the purported assassination plot as disinformation spread by adversaries hoping to spoil good relations between Russia and Iran.