Story highlights Iranian official thinks start of missile deliveries will occur before end of year, state media reports

Russia says progress in nuclear talks means embargo no longer needed

"We don't believe it's constructive at this time for Russia to move forward with this," U.S. says

(CNN) Russia has lifted a ban on the sale of a sophisticated air-defense system to Iran, drawing criticism from the United States and Israel.

"The big concern in the West ... and especially in Israel is that these Russian missiles will be able to help shield Iran's nuclear facilities from any future airstrikes," said CNN senior international correspondent Matthew Chance.

Russian Foreign Minister Sergey Lavrov said the move Monday to end the ban on shipping the S-300 anti-aircraft missile system to Iran was prompted by the recent progress in talks over Tehran's nuclear program. The ban had been in place since 2010.

"We are convinced that at this stage, there's no more need of such an embargo, Russia's separate voluntary embargo," Lavrov said, according to the Russian news agency Tass.

The decision was also applauded by Iranian Foreign Minister Javad Zarif, who called the move "a step in the right direction."

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