As world powers in Vienna continued talks with Iran over its nuclear program for the fifteenth straight day, demonstrators took to the streets in the Islamic Republic Friday in anti-Israel protests. Millions of Iranians took part in the protests in "cities across the country" to mark International Quds (Jerusalem) Day, Iran's Fars news agency reported. Iranian protesters burned Israeli, American, Saudi Arabian, and British flags in Tehran to mark the day. Protesters carried placards and chanted "Down with the US" and "Down with Israel," Fars reported. Quds day – initiated in 1979 by the Islamic Republic’s founder Ayatollah Khomeini – is an annual event of fiery anti-Israel protests in Iran held on the last Friday of Ramadan. Ayatollah Mohammad Taqi Vaezi, one of some 80 members of Iran’s Assembly of Experts that is a supervisory body around Iran’s Supreme Leader, was quoted Wednesday as saying that shouting the “Death to the Zionist regime” chant prevents Israeli “aggression.”Earlier in the week, Iran’s Foreign Ministry, according to the The Islamic Republic News Agency, issued a statement to mark the coming day, saying that the “restoration of lasting peace and tranquility in the Middle East can be attained through full observance of legitimate rights of oppressed Palestinian nation.” Nuclear talksIran's foreign minister said on Friday that talks between Iran and the six major powers had made some progress but were likely to continue during the weekend."Some progress has been made but we are not there yet ... I doubt it will happen today ... it seems that we are going to spend the weekend in Vienna," Mohammad Javad Zarif told reporters.Despite the ups and downs and missed deadlines in the nuclear talks , Jerusalem believes the the world powers will soon sign an agreement with Iran, paving its way to a bomb, senior officials in the Prime Minister's Office said on Thursday. US Secretary of State John Kerry said Thursday that the US is“absolutely prepared to call an end” to negotiations with Iran if Tehran does not make a series of “tough” political choices, quickly. But the US is not walking out yet, after blowing through its third deadline for those talks in just two weeks.Kerry said that neither he, nor President Barack Obama, nor their allies in the P5+1 powers (Britain, France, Russia, China and Germany) are willing to rush to complete a nuclear deal that would face a “test for decades.” Herb Keinon, Michael Wilner and Reuters contributed to this report.