point that it might be "wise" for Israel to preemptively attack Iran's nuclear research facilities. To destroy the facilities, while not a permanent solution to ending Iran's nuclear ambitions, he argued, might delay the progress of Iranian nuclear research for long enough that regime change could occur before the development of a nuclear weapon took place. He cited as an example the case of the apartheid government of South Africa, which renounced their efforts to pursue nuclear weapons after the Mandela government came to power. In April 2009, Army General David Petraeus said "the Israeli government may ultimately see itself so threatened by the prospect of an Iranian nuclear weapon that it would take preemptive military action to derail or delay it." On 17 September 2009, Ze'ev Elkin said that the delivery by Russia of S-300 missiles may prompt Israel to strike Iran. However, in June 2010 Russia voted for UN sanctions to prevent the S-300 missile sale. Iran consistently claimed that its nuclear program is purely for civilian purposes, and that it has no intention of ever utilizing its peaceful nuclear program to develop nuclear weapons. During the course of Iran's recent history, specifically during the Iran-Iraq war, Iran has experienced significant outages of its commercial electricity grid. Iran has also continuously claimed that it intends to ultimately export part of the electricity produced by its nuclear reactors to its regional neighbors, as a way of diversifying its mainly oil-based economy to more diversified revenue streams. German Defense Minister Thomas de Maiziere said in 2012 that an Israeli attack would be unlikely to succeed. Iran responding to Israeli threats Iran's former foreign minister, Manouchehr Mottaki declared that Israel was not capable of an attack and still recovering from the 2006 war in Lebanon. The Iranian Chief of the Revolutionary Guards, Mohammad Ali Jafari said Israel was within the reach of Iranian missiles and Iran would close the Strait of Hormuz, cutting off two-fifths of the global oil supply. Iran has the capability to close the Strait of Hormuz or impede traffic for a month or more, and any U.S. attempts to reopen it could escalate the conflict. According to Mohammad Ali Jafari "If Israel military aggresses against sovereignty and independence of the Islamic Republic of Iran, the country will use its right, established under international law which unequivocally establishes the right to defend its sovereignty by all lawful means