LAUSANNE, Switzerland, March 30 (Xinhua) -- Negotiations over Iran's nuclear program entered a critical phase on Monday with differences still remaining and the atmosphere here has changed from "optimistic" to some kind of "gloom" among negotiators.

As foreign ministers from all the P5+1 countries, namely the United States, Britain, France, Russia and China plus Germany, and the EU top envoy all gathering in Lausanne when the March 31 deadline for a framework agreement or understanding approaches, there were signs that a possible framework agreement might be within reach.

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."

By Xinhua

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