Hundreds of protesters demanding that Yemeni President Ali Abdullah Saleh end his more than 30-year-old rule were wounded in clashes with security forces in the capital Sanaa and the city of Taiz as pro-democracy rallies continue.

Riot police with batons were out in force, using tear gas and live fire against protesters in the capital.

"There have been at least 200 injured according to one medical source, and around 15 of those injuries are from live ammunition," she said.

"There were more than three hours of the constant sound of tear gas being fired, and live ammunition being fired. I could also see that there were snipers positioned on rooftops and they were firing down at the crowd."

Al Jazeera reported that the streets were littered with rocks and gas canisters, as police confrontations with tens of thousands of anti-government protesters continued in the capital.

In Taiz, the other main protest area, security police also used live ammunition and tear gas against some of the 100,000 people who marched there on April 9.

Al Jazeera's correspondent reported a "very heavy handed approach by the authorities" and an upsurge in violence in towns across Yemen.