Hundreds of thousands of anti-government protesters marched in Venezuela Thursday to demand the resignation of President Hugo Chavez. The event passed off peacefully, but the city's military air base was later the scene of a breakaway demonstration.

Thursday's demonstration marked three months to the day since eighteen demonstrators were shot dead during a similar march. That incident led to a two-day removal from power of President Hugo Chavez, after the armed forces withdrew their support.

On this occasion, there was no violence, despite the marchers' frustration at not being allowed to follow their planned route, past the presidential palace of Miraflores.

The intention had been to hand in letters demanding the resignation of President Chavez, who, for many in the opposition, is a dictator who wants to follow in the footsteps of Cuba's President Fidel Castro.

Mr. Chavez spent the day in the city of Maracay, one of his political and military strongholds. Later, as dusk fell, thousands lined the fence around the La Carlota air base in the capital hoping to meet with military leaders, while National Guard troops in riot gear reinforced the perimeter.

Opposition leaders addressed the apparently spontaneous breakaway demonstration, declaring a policy of civil disobedience.