Heavy fighting has continued in the centre of Sanaa, the Yemeni capital, between tribesmen and forces loyal to president Ali Abdullah Saleh.
Thousands more armed tribesmen are reported to be heading to the capital to battle the government forces.
Several days of fighting in the capital have claimed the lives of at least 40 people. This comes as the popular uprising and intense diplomatic effort have failed to persuade the president to give up.
Al Jazeera's Bernard Smith reports.
Source: Al Jazeera