Russia backs Iran nuclear programme

The agreement is the first between the two countries since Iran's 1979 Islamic revolution.

Despite opposition from Washington, Russian President Vladimir Putin has promised closer co-operation with Iran over its nuclear energy programme.

His pledge followed a meeting with Iranian President Mohammed Khatami, who is in Moscow for four days of talks on a range of issues, including controversial arms deals.

We believe that Iran must be an independent state capable of defending its national interests

President Putin

No agreements on arms sales were signed, but Mr Putin pledged to provide Tehran with weapons.

US State Department spokesman Richard Boucher said later on Monday: "It is up to the Russians and the Iranians to specify in more detail what they may or may not be doing. But this is an issue of great concern to us."

Mr Putin said that Russia would only provide Iran with "defensive" weapons, adding that such sales would not violate international agreements.

Iran wants to upgrade its weaponry

Russia says it has abided by international agreements banning the proliferation of nuclear and missile technologies.

But it paved the way for the planned arms sales by last year unilaterally scrapping a secret understanding with Washington that there would be no conventional weapons sales to Iran.

Nuclear weapon fears

Moscow has also brushed off repeated US demands that it cancel the $800m (£547m) Bushehr nuclear plant contract.

The United States claims the Russian technology could be used to develop nuclear weapons, but Moscow and Tehran argue that the plant can be used only for civilian purposes and will remain under international control.

The two leaders also used their Kremlin talks to oppose involvement by foreign countries in the energy-rich Caspian Sea area - an implicit criticism of US interest in the region.

"Iran is a key country in the region," Mr Putin said after he and Mr Khatami signed the first broad co-operation agreement between Moscow and Tehran since Iran's 1979 Islamic revolution.

Complex history

The BBC's Caroline Wyatt says relations between the two countries are based on mutual benefits and shared problems - the Iranian military needs arms and Moscow needs money.

President Khatami's visit does mark a step forward in a relationship that is becoming extremely friendly - but the two countries have a long and complex history.

In regional terms, they are rivals, so experts believe there are limits to how close they can get.