Experts from Iran and six world powers (known as the P5+1, or sextet) are gathering in Geneva for a third round of nuclear talks later in the day, aimed at setting a framework to implement last month’s landmark interim deal.

Two rounds of talks have been held so far since Tehran agreed on November 24 to suspend parts of its disputed nuclear program for six months in return for limited sanctions relief while a longer-term agreement is forged.

Iran’s Mehr news agency on December 29 quoted Iran’s top nuclear negotiator, Abbas Araqchi, as saying he hoped the deal could be implemented within a month.

Araqchi, however, said the talks are “proceeding slowly, as there are misunderstandings over the interpretation of some elements of the accord.”

The first round of talks was interrupted when Iranians walked out after Washington expanded its sanctions blacklist against Tehran.

Senate Foreign Relations Committee Chairman Bob Menendez (D) said at week’s end that the “Iranians are showing their true intentions,” following a statement Thursday by Iran’s nuclear chief, Ali Akbar Salehi, that his country is building a new generation of centrifuges for uranium enrichment but they “require further tests” before they can be mass produced.

Menendez is putting pressure on the administration by urging Congress to pass sanctions legislation against Iran, following the statement by Salehi.

“If you’re talking about producing more advanced centrifuges that are only used to enrich uranium at a quicker rate … the only purposes of that and the only reason you won’t give us access to [a military research facility] is because you’re really not thinking about nuclear power for domestic energy — you’re thinking about nuclear power for nuclear weapons,” said Menendez.

In addition, two officials familiar with Iran’s nuclear activities revealed to the Associated Press Friday that Iranian technical experts told counterparts from the six powers last week that some of the centrifuges have been installed at “a research tract of one of Iran’s enriching sites.”

Israel’s Minister Yuval Steinitz said last week that if sanctions on Iran had not been eased, Iran’s economy would have collapsed “in a year or two.”

Iran’s Fars news noted Monday that Iran announced in April that it could start enriching uranium to the purity level of 50 percent “if its research community declares a need to nuclear-fueled submarines,” but that it has no such plans at the moment.

“For now we have no plans for enrichment above 20 percent,” former Head of the Atomic Energy Organization of Iran (AEOI) Fereidoun Abbasi said at the time, and added, “But in some cases … such as ships and submarines, if our researchers have a need for greater presence under the sea, we must build small engines whose construction requires fuel enriched to 45 to 56 percent.”

“In this case, it’s possible we would need this fuel.”

“We have the capability to produce nuclear fuel for ships and submarines,” Abbasi said, and added, “But currently no plan to enrich uranium beyond 20 percent of enrichment is on our agenda.”