TEHRAN, Iran — Thousands of protesters defied Iran's highest authority Saturday and marched on waiting security forces that fought back with baton charges, tear gas and water cannons as the crisis over the disputed presidential election lurched into volatile new ground.
In a separate incident, a state-run television channel reported that a suicide bombing at the shrine of the Islamic revolution leader Ayatollah Ruhollah Khomeini killed at least two people and wounded eight. The report could not be independently evaluated due to government restrictions on journalists.
The reports could enrage conservatives and bring strains among backers of opposition leader Mir Hossein Mousavi. Another state channel broadcast images of broken glass and showed a witness saying only three people had been wounded.
Mousavi, who officials say finished second in the June 12 presidential election, appeared at a demonstration in southern Tehran and called for a general strike if he were to be arrested. "I am ready for martyrdom," he said.
He again called for nullifying the election's results, and opposition protesters swore to continue pressing their claims of a stolen election against Iran's embattled and increasingly impatient clerical leadership.
The extent of injuries in the street battles also was unclear. Some witnesses said dozens were hurt and gunfire was heard.
Some bloggers and Twitter users claimed that there had been numerous fatalities in Saturday's unrest.
The clashes along one of Tehran's main avenues had far fewer demonstrators than recent mass rallies for Mousavi. But they marked another blow to authorities who sought to intimidate protesters with harsh warnings and lines of black-clad police three deep in places.
Mousavi and his supporters claim that widespread fraud in the election robbed Mousavi of victory and kept hard-line President Mahmoud Ahmadinejad in office.
Mousavi bewildered many followers by not directly replying to the ultimatum issued Friday by Iran's supreme leader, Ayatollah Ali Khamenei: Call off demonstrations or risk being held responsible for "bloodshed, violence and rioting."
Information from the New York Times was used in this report.