TEHRAN, Iran (July 9, 2009)--Hundreds of protesters chanting "death to the dictator" were marching Thursday in Iran in defiance of the government's threat to "smash" any new marches.

Police armed with batons were using tear gas to break up the protests.

The witnesses say the number of protesters grew to about 700 as they marched toward the gates of Tehran University.

Soon after the confrontations began, mobile phone service was cut off in the capital.

For days, supporters of opposition leader Mir Hossein Mousavi have been trying to revive the large post-election protests that were crushed by security forces.