With a midnight deadline looming, Russia’s Foreign Minister Sergei Lavrov returned to Switzerland on Tuesday to rejoin nuclear talks with Iran. <br /><br /> Lavrov had left the negotiations in Lausanne on Monday, saying that he would only come back if there was a realistic chance of a deal.<br /><br /> Before making the return trip from Moscow, he voiced optimism about the prospects of success.<br /><br /> “The chances are high. They are probably not 100 percent but you can never be 100 percent certain of anything. But the odds are quite ‘doable’,” Lavrov told reporters.<br /><br /> With the clock ticking, all eyes are on the Swiss resort where six world powers and Iran are trying to overcome the final hurdles to a preliminary accord.<br /><br /> It is hoped this would be followed by a comprehensive deal by June 30 including all technical details on limits Tehran would place on sensitive nuclear activities in exchange for the easing of sanctions.<br /><br /> The United States is willing to continue working past Tuesday’s self-imposed midnight d