Iran's Foreign Ministry spokesman Ramin Mehmanparast has expressed optimism about the next round of talks between Tehran and the six major world powers (P5+1) in Baghdad, calling on the group “to take practical steps.”

“We are optimistic about the future of negotiations and want the other sides to put their words into action,” Mehmanparast told reporters in Zagreb, Croatia, on Wednesday, April 18 , Press TV reports.

He added that the latest round of Iran-P5+1 talks in Istanbul was held in a positive atmosphere, noting that the sides agreed to cooperate on the basis of the nuclear Non-Proliferation Treaty (NPT).

Iran and the P5+1 - Russia, China, Britain, France, the US and Germany - wrapped up their latest negotiations in Istanbul on April 14 and agreed to hold the next round of the talks in the Iraqi capital of Baghdad on May 23, 2012. Both sides hailed the talks as constructive.

Tehran and the five permanent members of the UN Security Council plus Germany previously held two rounds of talks, one in Geneva in December 2010 and another in Istanbul in January 2011.

The Iranian Foreign Ministry spokesman also blasted the United States for ‘violating’ the NPT regulations and said “Washington possesses half of the world’s atomic weapons.”

“There are certain countries which are threatening to use nuclear weapons if necessary. The U.S. and France are among such countries,” he stated.