| UNITED NATIONS
UNITED NATIONS President Barack Obama and Russian President Dmitry Medvedev on Thursday called for the speeding up of six-nation negotiations on a U.N. sanctions resolution against Iran over its nuclear program.
A White House statement said the two leaders discussed by phone the "good progress" being made by the United States, Russia, Britain, China, France and Germany toward agreeing on a fourth round of U.N. Security Council sanctions against Iran for refusing to halt its uranium enrichment.
They "agreed to instruct their negotiators to intensify their efforts to reach conclusion as soon as possible," the statement said.
Western nations fear that Iran's nuclear program is aimed at building atomic weapons. Tehran denies the charge, saying it only wants to generate electricity for civilian use.
Russia, like China, has close trade ties with Iran and has been reluctant to support new punitive measures against Tehran. Moscow eventually gave in but is supporting Beijing's push to dilute the proposed sanctions outlined in a U.S. draft.
As negotiators from the six powers work to hammer out a draft resolution, Brazilian President Luiz Inacio Lula da Silva is scheduled to head to Tehran this weekend to help mediate.
"It is not impeding progress ... on reaching agreement at all," said U.S. Ambassador to the United Nations Susan Rice when asked by reporters in New York if the Brazilian mediation efforts were undermining the push for a sanctions resolution.
"In fact, the P5-plus-one have been working intensively, regularly, both here and in capitals. I think we are making good progress," she said.
The "P5-plus-one" refers to the five permanent veto-wielding members of the Security Council and Germany.
"LAST BIG SHOT"
Rice said mediation was part of a two-track strategy the six powers are taking on Iran -- combining negotiations with threats of more sanctions -- and that progress on a sanctions resolution would probably "strengthen Lula's hand" in Tehran.
She added that she hoped Lula's message to Tehran would be that "pressure is mounting. Iran continues to have a choice. Assuming it continues to make the wrong choices, that pressure will intensify."
Brazil and Turkey, which hold rotating seats on the U.N. Security Council, have talked to Iran to try to revive a moribund agreement under which it would send low-enriched uranium abroad and receive a higher grade uranium in return.
"I think we would view the Lula visit as perhaps the last big shot at engagement," a senior U.S. State Department official told reporters in Washington.
U.S. officials stress in public that they support Brazil and Turkey's efforts while saying in private that should these fail, they hope countries will be more disposed to imposing a fourth round of Security Council sanctions against Iran.
Diplomats from the six powers met again in New York this week to discuss the draft resolution and overcome disagreements on details, U.N. envoys said.
Russia and China, they said, dislike an arms embargo, a ban on new investments in Iran's energy sector and other proposed steps in the draft and would like to see them softened.
Western diplomats have varying estimates on when the six powers will have a draft resolution ready to present to the 15-nation Security Council for debate, with some suggesting it could happen this month and others next month. But all said they hoped to see a vote on a resolution by June.
In addition to Brazilian and Turkish mediation efforts, several envoys said the six might wait for a major U.N. conference on the nuclear Non-Proliferation Treaty (NPT) that ends on May 28 before handing a resolution to the council.
Another complicating factor is that Lebanon holds the rotating presidency of the Security Council this month. Diplomats say that Lebanon, a nonpermanent council member until the end of 2011, would prefer not to have an Iran resolution reach the council in May.
The Iranian-backed militant group Hezbollah is in the Lebanese government, which means Lebanon will most likely not vote in favor of new sanctions against Iran, diplomats say.
(Additional reporting by Arshad Mohammed, Steve Holland and Matt Spetalnick in Washington; Editing by Paul Simao)