FACTBOX: Dim outlook for expanded sanctions against Iran

(Reuters) - Six world powers have told Iran to give a "serious response" at October 1 talks to U.N. demands that it suspend its nuclear program or face consequences, but they appear far from agreeing truly tough sanctions against Tehran.

There were signs in talks at the U.N. General Assembly opening of convergence between Western powers and Russia on the need for more sanctions if revived dialogue with Iran bears no fruit by the end of the year.

But Russia said nothing about what form new sanctions might take while China quickly dumped cold water on the very notion. Following is a rundown of salient points.

WHAT THE SIX WANT FROM TALKS WITH IRAN

Iran should shelve its proliferation-prone uranium enrichment program and open up to U.N. inspectors so they can verify Tehran has no covert project to develop nuclear weapons. In return, the Islamic Republic would qualify for a range of trade, technology and diplomatic benefits, offered since 2006.

WHAT IRAN WANTS

After long dodging direct dialogue, Iran now says it is willing to address ways of advancing non-proliferation and disarmament globally as part of talks spanning a wide range of world problems. But Tehran has repeated that its "sovereign right" to a nuclear program, which it insists is solely for civilian electricity generation, is not negotiable.

HARSH ENERGY SANCTIONS?

The United States, Britain and Germany suggest any expanded sanctions should squeeze Iran's vital oil sector, which could include its reliance on gasoline imports due to lack of refining capacity. Iran must import up to 40 percent of gasoline needs.

Critics say energy sanctions would hurt not Iran's elite but ordinary people, running the risk of uniting the public behind a government shaken by unrest over alleged election fraud.

Wednesday's six-power statement on Iran said nothing about future sanctions because the six do not all agree whether any are warranted, let alone what measures to impose, and when.

WESTERN-RUSSIAN CONVERGENCE SYMBOLIC SO FAR

After talks outside the U.N. General Assembly on Wednesday, U.S. President Barack Obama said he and Russian counterpart Dmitry Medvedev had agreed further sanctions should be looked at if Iran proved obdurate on enrichment.

"Sanctions are seldom productive but they are sometimes inevitable," said Medvedev. He was departing from Moscow's previous outright opposition to getting tougher on Iran after Washington, in a move that defused a fierce security row with the Kremlin, last week dropped plans for a missile shield in eastern Europe.

But crucially, no word on what Russia will do has yet come from Prime Minister Vladimir Putin, who handpicked Medvedev to succeed him as president and remains Russia's most powerful leader. Putin is seen as calling the shots on Iran, a hard-liner on Russian national interests including hefty trade stakes in the Islamic Republic that might not gel with energy sanctions.

Russia's prevailing stance has been that without hard proof Iran is trying to build atom bombs, there is no need to isolate it. Rather, it has said, this could be counterproductive.

CHINA HOLDING OUT

"We believe that sanctions and exerting pressure are not the way to solve problems and are not conducive for the current diplomatic efforts on the Iran nuclear issue," Foreign Ministry spokeswoman Jiang Yu told a news conference on Thursday.

Her remarks suggested China, which often says there should be no interference in the internal affairs of other countries, could retard any buildup of international heat on Iran.

Market sources said this week state-run Chinese firms are selling gasoline to Iran, stepping into a vacuum left by Western exporters succumbing to political pressure to stay away.

NEXT STEP ON SANCTIONS

No decision is likely before the end of the year and the next batch of sanctions is likely to be no little more than symbolic given Russian and Chinese reservations. A deal may be limited to adding more Iranian firms and individuals to existing U.N. blacklists for asset freezes and travel bans established in three previous rounds of sanctions adopted since December 2006.

Iran's counterproposal for talks and new concessions to U.N. nuclear inspectors, such as tighter monitoring of its Natanz enrichment plant -- both praised by Russia -- may have won it a few more months of breathing space from any sanctions hammer.

(For a related news story please click on [nSP175038])

(Additional reporting by Guy Faulconbridge in Moscow and Ben Blanchard in Beijing; Writing by Mark Heinrich; Editing by Jon Boyle)