Iran's U.N. Envoy, Denouncing Sanctions, Says Nuclear Talks Are at "Critical Point" Iran's ambassador to the United Nations said Friday that negotiations with the big powers over the disputed Iranian nuclear program had reached a "critical point," implicitly raising the possibility of failure, because of the new regimen of harsh economic sanctions that have just been imposed on his country by the United States and European Union. "This by itself indicates that they are not willing to engage with us in a meaningful dialogue," the ambassador, Mohammad Khazaee, told reporters at a news conference convened by Iran's United Nations mission to present its view of the nuclear negotiations, which have made scant progress after three rounds of high-level talks since April. A meeting of lower-level negotiators representing Iran and the so-called P5-plus-1 group of nations - the five permanent members of the United Nations Security Council plus Germany - is set for Tuesday in Istanbul. Mr. Khazaee rarely holds news conferences, and the timing suggested that Iranian officials were posturing to lay the groundwork for possible disappointment or worse at the meeting in Turkey. While he expressed hope for progress, he said, "at the same time it is clear to us that some members of the 5-plus-1, for whatever reasons, obviously and mainly political reasons, are not forthcoming and serious enough for finding a solution." "If the talks do not proceed as they should," he added, "we are going to have another standoff in the talks. Therefore, we can say that we are at a critical point in our talks with some members of the 5-plus-1. He spoke a day after a new American law took effect that penalized countries that did business with Iran's central bank by denying their banks access to the United States market. Twenty nations that had significantly reduced their reliance on Iranian oil were exempted from the law, including China, Iran's biggest customer. On Sunday, the European Union will invoke a potentially more damaging sanction on Iran, banning imports of Iranian oil and prohibiting Europe-based insurers from covering Iranian oil shipped anywhere. That measure has already caused havoc for Iran as well as many non-European customers because Europe dominates the maritime insurance business. American and European diplomats have said Iran's willingness to even talk about its nuclear program is the result of pressure from the sanctions, which have already caused a plunge in Iran's exports of oil and contributed to a sharp rise in inflation there. Mr. Khazaee restated Iran's longstanding contention that the sanctions had to be rescinded before negotiations could succeed. But he also said sanctions pressure, no matter how damaging, would do nothing to change the Iranian position in the dispute. "We have learned how to cope with these problems," he said. The P5-plus-1 group has said Iran must abide by Security Council resolutions that demand that it halt enrichment of uranium and answer questions about activities that United Nations nuclear inspectors have raised regarding possible military applications of the Iranian nuclear program. Iran contends that the Security Council resolutions are invalid because Iran has signed the Treaty on the Nonproliferation of Nuclear Weapons, which entitles it to enrich uranium for peaceful purposes. Iran has also said that its supreme leader, Ayatollah Ali Khamenei, has banned nuclear weapons as un-Islamic. Mr. Khazaee reiterated those points and criticized what he called the West's double standard of suspecting the motives of Iran but not those of Israel, which has nuclear weapons and has not signed the nonproliferation treaty. Israel has never officially acknowledged its nuclear arsenal, but it is believed to have 75 to 200 nuclear weapons, according to the Arms Control Association, a Washington-based group.