At least four anti-government protesters were killed when armed government supporters intercepted a march of thousands of protesters demanding ouster of Yemeni President
Ali Abdullah Saleh in the country's capital on Monday, a security official said, Xinhua reported.
"Two more protesters died of serious gunshot in their chests in a hospital in the capital Sanaa, hours after two were killed on the spot on Monday afternoon," the official, who commands a police squad to break out the clashes, told Xinhua on condition of anonymity.
"Around ten other protesters were wounded with gunshot in hands and legs, while another 40 protesters and ten government supporters suffered suffocation from gas bombs launched by the policemen," the official added.
The fighting was the first of its kind since President Saleh was hospitalized in Riyadh on June 4 to treat injuries he sustained in an assassination bomb attack on his presidential palace in Sanaa.
The protesters shouted slogans against the 33rd anniversary of Saleh's rule while marching from their six-month-long epicenter sit-in square near Sanaa University towards a main street leading to Saleh's palace.
Protesters on Sunday vowed to escalate their demonstrations to press for toppling Saleh from power by trespassing "streets leading to the presidential palace, state media and intelligence buildings."
Similar protests were also held in major provinces of Saada, Taiz, al-Hodayda, Ibb and Thamar.
Saleh wrote an article published by the Yemeni state media on Monday morning on the occasion of the 33rd anniversary of his rule, in which he described his opponents as "traitors" and asked them to keep away from violence and respond positively to the vice president's call for dialogue to end the long-running political deadlock.