(Bloomberg) -- Iran and world powers are closing in on an agreement detailing the main steps needed to resolve a 12-year standoff over the Islamic Republic�s nuclear program, giving themselves three months to overcome remaining differences.

Though any understanding is likely to stop short of the full resolution of every issue dogging the dispute, a statement may be released after Russian Foreign Minister Sergei Lavrov returns to the talks this afternoon, according to two officials involved who spoke on condition they not be named in line with diplomatic protocol. The sides would then have until June 30 to draft a detailed technical accord.

An agreement can be reached �as long as none of the participants at the talks raise their stakes at the last moment,� Lavrov said at a press conference prior to returning to Lausanne, Switzerland, where the negotiations are taking place. One sticking point remained the lifting of United Nations sanctions as demanded by the Iranians, according to an official involved in the talks.

The accord on main principles would be less than what was sought by President Barack Obama. He needs to sell any deal to a skeptical Congress and American public to get support for a 10-to 15-year accord that would restrict and monitor Iran�s nuclear activities in exchange for relief from crippling sanctions on banking, oil and other trade.

It would though allow his administration to say it met a self-imposed March 31 deadline for a political understanding as it seeks to head off new sanctions on Iran proposed by Congress. The president says such a move could derail talks.
Oil Decline
Oil fell as signals emerging from Lausanne suggested some form of accord was likely. Futures dropped as much as 2.9 percent in New York, falling for a third day.

If a final deal is reached by June 30, Iran could add more crude to an oversupplied oil market where prices have fallen more than 50 percent since June. Iran has stored excess crude on tankers for the past 2 1/2 years as restrictions deterred buyers, according to the International Energy Agency. The country now exports about 1 million barrels of crude per day, down from 2.5 million in mid-2012, IEA data show.

German Foreign Minister Frank-Walter Steinmeier earlier Tuesday said envoys were working to iron out �a bit of a crisis� and that new ideas were being exchanged.

�There are different formulas, either to lift them or first to suspend them,� Lavrov said at the Moscow briefing referring to the easing of sanctions. �The point is that in practice the sanctions should no longer be in effect and shouldn�t prevent the development of legitimate economic and trade interests.�
Remaining Hurdles
An Iranian website associated with conservatives who oppose major concessions said a new UN resolution is being discussed that would remove sanctions on Iran after the Persian Gulf country had met certain conditions.

The sticking point is that the U.S. and France want a snapback mechanism that automatically reimposes the curbs should Iran violate the agreement, Irannuc.ir said. Iran, Russia and China reject that notion, instead arguing that the issue should go to arbitration, it reported.

Other unresolved issues involve the length of any agreement, the extent of Iran�s research and development and Iran�s stockpile of enriched uranium, it said.
Ending Isolation
The group of six powers -- China, France, Germany, Russia, the U.K. and the U.S. -- is attempting to ensure Iran�s program is peaceful, amid charges over the years that the nation is seeking to obtain nuclear weapons. Iran denies the claims.

A framework understanding on Tuesday would be a first step toward ending Iran�s economic isolation and allowing the country with the world�s fourth-biggest oil reserves to export freely after a final agreement is reached by June 30, and once Iran proves compliance with initial restrictions.

A failure in talks would have been a blow to Obama, who has backed two years of negotiations with Iran despite domestic opposition. Republicans and many Democrats in Congress say they agree with Israeli Prime Minister Benjamin Netanyahu�s argument that the emerging accord is dangerous.

The stakes are also high for Iranian President Hassan Rouhani, elected as a reformer to fix an economy whose GDP and currency were battered under wide-ranging economic sanctions on energy, banking and shipping, among other restrictions on trade and investment. Rouhani said the removal of penalties must be �a fundamental part of this agreement� and that it was �the other side�s turn to take the final steps,� the Fars news agency reported Sunday.

By Bloomberg