Lausanne, March 30, (RHC) -- Senior negotiators from Iran and the United States wrapped up another day of negotiations on outstanding issues pertaining to Tehran’s nuclear program in the Swiss city of Lausanne.

The meeting between Iranian Foreign Minister Mohammad Javad Zarif and U.S. Secretary of State John Kerry ended on Sunday as Iran and the P-5 +1 countries are holding sensitive negotiations aimed at reaching a general understanding on sticking points ahead of a looming end-of-March deadline.

However, a diplomatic source told Xinhua on Monday that there are still many uncertainties in announcing any achievements.

"It seems that they might be too much optimism at the beginning," the source said.

According to the source who don't want to be named, the possibility for the sides to reach a common understanding on Monday is very little, if still exist.

If after the final efforts the foreign ministers could announce something, the source said, it may be in a form of an agreement, but looks more likely to be a "declaration," "statement" or just a "press briefing statement."