text: BEIRUT — Tens of thousands of Syrians shouting "We want freedom!" carried slain protesters through the streets Saturday as opposition figures meeting in Turkey called for a united front to bring down the 40-year ruling dynasty of the Assad family.
  Syrian security forces killed at least 28 people Friday during the largest protests since the uprising began more than four months ago, activists said. Hundreds of thousands of people poured into the streets nationwide, but they were met with gunfire and tear gas.
  "The regime has kidnapped the entire state, and we want it back," said Haitham al-Maleh, one of Syria's most prominent dissidents, who led Saturday's opposition conference in Istanbul. The 80-year-old lawyer spent years in Syrian prisons for his political activism.
  Syria's crackdown on the protests has led to international condemnation and sanctions. U.S. Secretary of State Hillary Rodham Clinton said Saturday that President Bashar Assad had dashed hopes of reform.
  "What's happening in Syria is very uncertain and troubling because many of us had hoped that President Assad would make the reforms that were necessary," she said in Istanbul. "The brutality has to stop, there must be a legitimate sincere effort with the opposition to try to make changes."
  "Yesterday we witnessed the largest demonstrations to date in Syria, an effort to try to convey directly to the government the pent-up desire of the Syrian people for the kind of reforms that they have been promised," she added.
  Activists say the government's crackdown has killed some 1,600 people since March, most of them unarmed protesters. But the regime disputes the toll and blames a foreign conspiracy for the unrest, saying religious extremists — not true reform-seekers — are behind it.
  Saturday's conference was an attempt to form a unified movement that can offer a realistic alternative to Assad, whose supporters argue that he is the only force who can guarantee stability in a region bedeviled by civil wars and religious strife.
  Although Assad's regime is shaken, he still draws from a significant well of support from the middle classes, business community and religious minorities.
  Still, the uprising appears to be gaining momentum.
  Witnesses told The Associated Press that tens of thousands from Damascus and the suburbs held funerals for slain protesters Saturday, carrying the bodies overhead on stretchers and shouting "God is Great!" and "We want freedom!"
  Like most witnesses in Syria, they spoke on condition of anonymity for fear of retribution.
  Witnesses also said security forces opened fire on anti-government protesters in the eastern border town of al-Boukamal near Iraq's border, killing at least one protester and wounding others.
  State-run Syria TV contested that, however, and said gunmen killed two police officers in al-Boukamal and armed groups stormed a police headquarters and confiscated weapons.
  The government has banned most foreign media and restricted local coverage, making it difficult to independently confirm accounts on the ground.
  A small group of activists in Damascus also took part in Saturday's opposition meeting, but they had to join by telephone. The opposition had planned to hold dual meetings in Damascus and Istanbul, but the location in Syria was besieged by security forces on Friday, forcing them to scale back their plans. Activists say 14 protesters were killed Friday in the Damascus neighborhood of Qaboun, where the conference was to be held.
  Opposition figure Mashaal Tammo, addressing the conference by phone from Damascus, said Assad had lost his legitimacy to rule and called on him to step down.
  "The existence of the regime is no longer justified," he said.
  AP Writer Matthew Lee contributed to this report from Istanbul.