TEHRAN, Iran - Protesters battled police over Iran's disputed election and shouted their opposition from the rooftops yesterday, but President Mahmoud Ahmadinejad dismissed the unrest as little more than "passions after a soccer match" and drew his own huge rally of support.

Just after sundown, cries of "death to the dictator" echoed through Tehran as thousands of backers for Ahmadinejad's rival, Mir Hossein Mousavi, heeded a call to bellow from the roofs and balconies. The deeply symbolic act recalled the shouts of "Allahu Akbar," or "God is great," to show opposition to the Western-backed monarchy before the 1979 Islamic Revolution.

The scenes summed up the showdown over the disputed elections: a confident Ahmadinejad exerted control, while Mousavi showed no sign of backing down and could be staking out a role as powerful opposition voice.

His charges that Friday's vote was riddled by fraud brought sympathetic statements from Vice President Joe Biden and other leaders.

With his wide network of young and middle-class backers, Mousavi could emerge as a leader for Iran's liberal ranks and bring internal pressure on Ahmadinejad and Iran's theocracy to take less confrontational policies toward the West.

Meanwhile, the crackdown on dissent following the disputed elections puts the Obama administration in a tougher spot, as it sticks with diplomacy as the best way to end that country's nuclear weapons program.

Biden said yesterday that efforts to engage Tehran, with the central goal of halting its pursuit of nuclear weapons, will continue. But the charges of vote fraud and the battles between police and opposition protesters appear to be major setbacks for the new U.S. administration's policy.

Biden made clear yesterday that the administration, while uncertain of the implications of Ahmadinejad's electoral victory , has no intention of abandoning its Iran policy. President Obama has put Iran at the center of his policy of extending an open hand to adversaries; the Iranians so far have responded mainly with silence.

On another front, Biden yesterday committed the United States to enforcing new U.N. penalties against North Korea while acknowledging that "God only knows" what ruler Kim Jong Il wants from the latest showdown.

The sanctions are aimed at depriving the reclusive communist country of the financing used to build its nuclear program.

"It is important that we make sure those sanctions stick and those sanctions prohibit them from exporting or importing weapons," Biden said.

"This is a matter of us now keeping the pressure on." *