Six world powers are holding a new round of talks with Iran in Moscow to try to resolve international concerns about the Iranian nuclear program and avoid a collapse of diplomacy that could raise the threat of conflict.

European Union foreign policy chief Catherine Ashton, who represents the six-nation group, began meeting with Iranian diplomats in the Russian capital Monday for two days of scheduled negotiations. The two sides resumed talks in April after a 15-month stalemate and met again in Baghdad last month, but appeared to achieve little more than agreeing on another negotiating round in Moscow.

An Iranian delegate at the talks told Iran's state-run news agency IRNA that the latest talks will fail if the world powers do not recognize what Tehran sees as its right to enrich uranium. Iran says its enrichment work is for peaceful uses including electricity generation and medical research. But, Israel and Western powers accuse Iran of trying to develop nuclear weapons under cover of a civilian energy program.

The Iranian delegate said Iran does not fear a failure of the Moscow talks and will not agree to further negotiations unless the six-nation group accepts a five-point Iranian proposal offered in Baghdad.

The world powers have been pressing Iran to stop enriching uranium to 20 percent purity, a level that some see as a short-step from the higher purity needed for nuclear weapons. The six-nation group also has been calling for Iran to remove stockpiles of highly-enriched uranium from its territory and shut down an underground facility at Fordo that has been producing the material.

In return, the world powers have offered to send Iran nuclear fuel for its medical research reactor and badly-needed spare parts for its aviation industry. Iranian leaders have dismissed such offers in the past as insufficient.

The United States and European Union have been increasing pressure on Iran to compromise by tightening unilateral sanctions targeting Iranian oil exports, a major source of the nation's income. A complete EU embargo on Iranian oil is set to begin on July 1, while Washington plans to launch sanctions on businesses dealing with Iran's oil industry several days earlier.

Russia hopes the new talks will achieve enough progress to lead to more negotiations and prevent a diplomatic failure that could lead to foreign military intervention in Iran, a longtime economic partner of Moscow.

Israel sees a nuclear-armed Iran as a threat to its existence and has hinted that it could strike Iranian nuclear sites within months to remove that threat. World powers have expressed concern that an escalation of the dispute into a regional war would trigger a jump in oil prices and depress the fragile global economy.