A prominent Egyptian dissident said Saturday he was attacked by an assailant on a motorcycle who ignited a flammable substance in his face, leaving his head burned. Ayman Nour, one of the few liberal campaigners for democracy in Egypt, spent nearly four years in prison after challenging the country's longtime president, Hosni Mubarak, in a 2005 election. He said after his release in February he would continue his campaign for democracy. Nour accused elements within Mubarak's ruling party of being behind the attack on him, which occurred Friday night. "This (attack) is wrong. This is the wrong message, for the wrong reason at the wrong time," he said. The attack came a day after he pledged to supporters that he would run again for president in 2011 if his political party nominates him. It also came soon after Nour petitioned Mubarak, 81, to remove restrictions on his political and civic rights and criticized a major committee in the ruling party headed by Mubarak's son, who is said to be positioned to succeed his father. The attack against Nour comes two weeks before US President Barack Obama visits Egypt, where he is expected to address the Muslim world in a speech. The Obama administration has hinted it will not hinge its relationship with Egypt on human rights demands, upsetting some of Egypt's activists. Nour said he was leaving his house Friday night in an upscale neighborhood in Cairo when a young man on a motorcycle called his name. When Nour looked toward the biker, a flame about a meter and half shot toward him. "The fire caught my hair, leaving 20 percent of it burned. My forehead and the left side of my face are burned. My clothes caught fire," he said in a telephone interview, refusing to meet face to face with reporters because he said he felt embarrassed. Nour said he has postponed many of his public appearances and appointments for the next couple of weeks until he heals and his hair starts to grow back. Nour said he filed a police report and that he has no doubt the attack was premeditated. "It couldn't have been from any other direction" but the ruling party, in control for nearly three decades. A ruling party official said he was not aware of the attack and he had no immediate comment about the accusations. Nour has been rallying since his release for more freedom. He said he has been prevented from going back to practice law, appearing on national television, selling property or opening a bank account. "This is killing me," Nour said. Over the last week, Nour was vocal about his grievances. He marched to the presidential palace with a group from his al-Ghad, or Tomorrow, party on Monday to petition the president to uphold a court decision backing his right to lead his fragmented political party. The court decision, he said, was ignored by a ruling party-controlled committee, which has the right to accept or refuse political parties. In an appearance Thursday, Nour also criticized a ruling party policy committee headed by Mubarak's son, Gamal. "Apparently this was provocative to some," he said. "The more there is extremism in confronting us, the more we believe that the solution in Egypt will only come with change, not reform." Nour said the attack wouldn't prevent him from meeting Obama if he asked for an audience with him. Obama is scheduled to come to Egypt first week of June. "He should ... ask to meet representatives from the opposition. I will go meet him with a cap." In an op-ed in the Washington Post on Saturday, a fellow activist for democracy in Egypt said she hoped Obama's visit would not be seen as supporting what she called the Egyptian government's policy of silencing dissent. "We urge the president to affirm that forging alliances with the people of the Middle East rather than those who oppress them is the key to eliminating extremism and bringing about lasting regional and international stability and security," wrote Dina Guirguis.