Iran notified the IAEA that it would resume uranium conversion at Esfahan. In February 2006 Iran ended its voluntary implementation of the Additional Protocol and resumed enrichment at Natanz, prompting the IAEA Board of Governors to refer Iran to the UN Security Council. After the vote, Iran announced it would resume enrichment of uranium. In April 2006 Ahmadinejad announced that Iran had nuclear technology but said that it was purely for power generation, not weapons. In June 2006 the EU 3 joined China, Russia, and the United States, to form the P5+1. The following month, July 2006, the UN Security Council passed its first resolution (nr. 1696), demanding Iran stop uranium enrichment and processing, because of "serious concern" about "a number of outstanding issues and concerns on Iran's nuclear programme, including topics which could have a military nuclear dimension". Another UN Security Council resolution followed in December 2006 (nr. 1737); others followed later. The legal authority for the IAEA Board of Governors referral and the Security Council resolutions derived from the IAEA Statute and the United Nations Charter. The resolutions demanded that Iran cease enrichment activities, and the second resolution (Dec. 2006) also imposed sanctions on Iran, including bans on the transfer of nuclear and missile technology to the country and freezes on the assets of certain Iranian individuals and entities, in order to pressure the country. In July 2006 Iran opened the Arak heavy water production plant, which led to one of the Security Council resolutions. Four more UN Security Council resolutions concerning Iran's nuclear program followed: 1747 (March 2007), 1803 (March 2008), 1835 (September 2008), and 1929 (June 2010). In Resolution 1803 and elsewhere the Security Council acknowledged Iran's rights under Article IV of the NPT, which provides for "the inalienable right ... to develop research, production and use of nuclear energy for peaceful purposes". In a February 2007 interview with the "Financial Times", IAEA director general Mohamed ElBaradei said that military action against Iran "would be catastrophic, counterproductive" and called for negotiations between the international community and Iran over the Iranian nuclear program. ElBaradei specifically proposed a "double, simultaneous suspension, a time out" as "a confidence-building measure", under which the international sanctions would be suspended and Iran would suspend enrichment. ElBaradei also said, "if I look at it from a weapons perspective there are much more important issues to me than the suspension of [enrichment]," naming his top priorities as preventing Iran from "go[ing] to industrial capacity until the issues are settled"; building confidence, with "full inspection" involving Iranian adoption of the Additional Protocol; and "at all costs" preventing Iran from "moving out of the [treaty-based non-proliferation] system".