Protesters receive aid after inhaling tear gas following clashes with police in the southern Yemeni city of Taiz on Sunday. Stringer/Reuters

Thousands of women calling for the ouster of Yemen's longtime ruler were attacked Sunday by police with sticks and rocks, setting off a furious battle with male protesters that left several people hurt, activists said.

The women were marching down a main street in the southern town of Taiz shouting "Peaceful! Peaceful!" when they were attacked, activist Ghazi al-Samei said.

Three young men suffered serious gunshot wounds when police opened fire, protester Bushra al-Maqtari told The Associated Press by telephone. She said at least 200 more suffered breathing problems caused by inhaling tear gas.

Army tanks and armoured cars stopped other demonstrators from entering Taiz, the site of some of the largest and angriest protests against President Ali Abdullah Saleh's rule.

Protesters have been camping out in main squares throughout Yemen for weeks, demanding Saleh immediately leave power after 30 years. The president has offered to resign by the year's end and says leaving without a negotiated transition, would lead to chaos. On Saturday, opposition groups demanded he hand power to his vice-president and set up committees to thrash out constitutional reform and elections.

The president's spokesman, Ahmed al-Sufi, said Sunday that Saleh is only "ready to discuss the peaceful handover of power according to the constitution."

Saleh's top security official in Taiz, Abdullah Qiran, is accused by demonstrators of orchestrating some of the most brutal crackdowns against demonstrators, particularly in the southern port town of Aden, where he was previously stationed.

Some 48 demonstrators were killed there over a period of weeks by security forces and Saleh supporters armed with sticks, knives and guns.

At least 97 demonstrators have been killed in Yemen since protests began on Feb. 11, according to the Yemeni rights group Shakayek. About 49 were killed several weeks ago when snipers on rooftops opened fire at demonstrators in the capital, Sanaa.