Despite continuous talks and marathon meetings between Iran and the world powers, gaps still remain between the parties’ positions.

Iran's foreign minister met again with the six world powers in Lausanne, Switzerland on Tuesday morning in a last-ditch effort to reach a breakthrough in stalled negotiations, with just 16 hours to go before the deadline expired for a "framework agreement" over its contentious nuclear program

Despite continuous talks and marathon meetings between Iran and the world powers - - the United States, Russia, China, Britain, France and Germany — at this city’s Beau Rivage Palace Hotel Monday, gaps still remain between the parties’ positions.

The sides have until midnight Lausanne time to reach an agreement.

Russian Foreign Minister Sergei Lavrov was not present at the meeting, having left Lausanne and returned to Moscow a day earlier. The Russian foreign ministry said that Lavrov was planning to return to Lausanne on Tuesday afternoon, and that he would hold a press conference on the talks just before departing Moscow.

The American team began showing signs of irritation at Iran’s conduct Monday afternoon, with acting State Department spokeswoman Marie Harf saying in an interview with CNSNews.com that the time had come to see whether the Iranians were capable of taking decisions. “So we really need to see from the Iranians if they’re willing to get to yes here,” she said.

“Everyone knows that Congress is waiting to act if we can’t get to an agreement,” she noted.

The Iranians also put up a tough front. The head of the country’s negotiating team, Deputy Foreign Minister Abbas Araghchi, said in an interview with Iranian television that he hoped it was possible to reach an agreement by the Tuesday midnight deadline, but that there were still significant gaps, especially on technical issues related to Iran’s nuclear program.

He said it was the nuclear experts of one of the participating world powers that was putting up obstacles and conveyed a veiled threat by saying that the deadline might be missed, in which case the talks would have to continue in a different forum.

By Haaretz