LAUSANNE, Switzerland�Russia�s foreign minister is planning to return to the Iranian nuclear talks in Switzerland on Tuesday afternoon ahead of the deadline to forge the political outlines of a final deal, a spokeswoman said.

Sergei Lavrov�had left the talks on Monday afternoon to head back to Moscow and at the time, his office said he would return to the talks if needed. His return may signal a political agreement can be reached in the coming hours.

The spokeswoman said Mr. Lavrov would hold a news conference at 11 a.m. local time in Moscow and would likely comment on the nuclear talks.

Iran and six global powers set Tuesday as the deadline to agree the main parameters of a final agreement that must be in place by June 30.

The French and German foreign ministers will also stay at the nuclear talks and not return to a planned meeting in Berlin, the German foreign office said Tuesday morning.

While diplomats say that sealing the political framework wouldn�t guarantee diplomatic success in June, it would be the biggest breakthrough in more than 12 years between Iran and the six powers, the U.S., the U.K., Russia, China, France and Germany.

At the heart of the deal would be concrete steps by Iran to ensure the country couldn�t swiftly break out toward building a weapon in exchange for the easing and eventual lifting of tight international sanctions on Tehran.

Except for Mr. Lavrov, the foreign ministers from the other six powers and Iran are all gathered in Lausanne.

Senior officials and experts held discussions through much of the night in a bid to resolve the two remaining key problems�the pace at which United Nations Security Council sanctions would be eased and what kind of nuclear research Iran will be able to do in the final years of an agreement.

By The Wall Street Journal