Iran on Tuesday set September 1 as a possible date for the resumption of nuclear talks with six world powers which have been stalled since October, but insisted conditions set by Tehran must first be met. Iran at the same time rejected claims by some of its officials that airports in Britain, Germany and the United Arab Emirates had refused to refuel its passenger planes, in line with latest US sanctions on Tehran. Iran's state news agency IRNA reported that the country's top nuclear negotiator Saeed Jalili, in a letter to European Union foreign policy chief Catherine Ashton, said that Tehran needed three issues clarified by the world powers before it could consider resuming talks. Ashton, who is negotiating with Iran on behalf of the so-called P5+1 powers - Britain, China, France, Russia, the United States and Germany - had invited Tehran for talks soon after the UN Security Council imposed new sanctions on the Islamic republic on June 9. Jalili said the world powers must answer whether the talks are aimed at “engagement and cooperation or continued confrontation and hostility towards Iranians.” “Will you be committed to the logic of talks which calls for avoiding threats and pressure?” he asked, and added that the six powers must air a “clear view” on the “Zionist regime's nuclear arsenal.” Israel, which has the Middle East's sole if undeclared nuclear arsenal, has backed US-led efforts to prevent Iran developing a nuclear weapons capability through sanctions, but has also refused to rule out military force. Iran insists that its nuclear programme is aimed solely at peaceful purposes and says that the international community should focus on Israel, which, unlike Iran, is not a signatory to the nuclear Non-Proliferation Treaty. “Your response to the above questions can pave the way for forming talks to allay common global concerns for peace and justice with the presence of other interested countries from September 1,” Jalili told Ashton, according to IRNA. On June 28, President Mahmoud Ahmadinejad declared a two month freeze until late August on talks with world powers over Iran's nuclear programme, saying it was a “penalty” for backing new UN sanctions on Tehran. Maja Kocijancic, the spokeswoman for Ashton, welcomed Iran's readiness to talk, but told reporters in Brussels that the dialogue “would have to be on the nuclear programme of Iran.” Foreign ministry spokesman Ramin Mehmanparast meanwhile said on Tuesday that Iranian passenger planes were being refuelled at airports in Britain, Germany and the United Arab Emirates, contrary to the comments of some Iranian officials. “The refuelling of our planes is continuing,” Mehmanparast said. On Monday, Mehdi Aliyari, secretary of the Iranian Airlines Union, told ISNA news agency that Iranian planes were being refused fuel at airports in the three countries. His allegations were repeated by other Iranian officials.