TEHRAN (AFP) - Iran's supreme leader Ayatollah Ali Khamenei urged world Muslims on Wednesday to join the Palestinian "resistance" against Israel, but his call was dismissed by Palestinian President Mahmud Abbas. "The only way to save Palestine is resistance," Khamenei said in his address to open a two-day global summit Tehran organised in aid of Gaza and the Palestinians. "Support and help to Palestinians is a mandatory duty of all Muslims. I now tell all Muslim brothers and sisters to join forces and break the immunity of the Zionist criminals." Khamenei said any negotiations to solve the Israel-Palestinian issue were fruitless, adding that the US and Britain committed the "crime of creation and supporting this cancerous tumour (Israel)." "Even the new President of the US who came to power with the motto of changing the (George W) Bush administration's policies talks about unconditional commitment to secure Israel. This is defending terrorism by a government." But Khamenei's call was bluntly dismissed by Abbas after he met US Secretary of State Hillary Clinton, who is on her first visit to the region since taking office. "We are sending a message to the Iranians and others - stop interfering in our affairs," Abbas said. "They are interfering only to deepen the rift between Palestinians." Top Hamas leaders Musa Abu Marzuk and Abu Zahar from the Islamist Hamas movement that controls Gaza and who attended the Tehran summit acknowledged the role Iran played in tackling the Middle East problem. Marzuk told delegates Hamas "wanted national unity talks to succeed ... but a unity which satisfies the Palestinian people and not a pact which compromises their rights." "We welcome plans to reconstruct Gaza, but if there is a condition which is against Palestinian people's principles, we will not accept it," he said. Zahar openly said Iran and other countries have been offering aid to Palestinians, which included "paying salaries of our employees since we came to power in 2006." On Tuesday, Saudi Foreign Minister Prince Saud al-Faisal called for a joint Arab strategy to deal with the "Iranian challenge" at a meeting of Arab foreign ministers in Cairo. "In order to cement Arab reconciliation we need a common vision for issues that concern Arab security and deal with the Iranian challenge," including its nuclear drive, he said. In his address at Wednesday's Tehran summit, Iranian President Mahmoud Ahmadinejad called for setting up a "global anti-Zionist front." "On the other hand we must seriously pursue punishing the Zionist criminals, so that by saving Palestine and the establishment of a popularly chosen government, the world gets rid of racism, lies and occupation forever," he told the conference. Prominent Iranian lawmaker Khazem Jalili said the Tehran conference will suggest setting up a common fund of participating nations to channel the donations. But "unfortunately, the route for delivering the aid is not open," he said referring to the Gaza crossings that have been blocked by Israel. The summit, attended by officials from such neighbours as Kuwait and Bahrain, as well as countries such as South Africa and Nigeria, comes two days after global donors meeting in Egypt pledged to donate around 4.5 billion dollars to rebuild Gaza.