Yemeni security forces and pro-government loyalists clashed with crowds demanding an end to President Ali Abdullah Saleh's 32-year rule in several cities on Friday. At least four people were killed and dozens wounded.
Al-Jazeera reported that three people died as police tried to disperse crowds in the southern city of Aden, where resentment against rule from Sanaa runs high. Protest organizers had billed as the rallies as a nationwide "Friday of Rage."
Thousands demonstrated across Aden, angered by the killings of six people earlier this week and chanting anti-Saleh slogans such as "Ali, listen, the people want you out."
One protester was also killed and seven wounded in Taiz, 130 miles south of Sanaa, when an assailant threw a hand grenade at them, opposition sources and witnesses said.
'Terrifying' "The car got close to the square and someone threw a bomb that exploded in the middle of the protesters, it was terrifying," he said, declining to be named.
Several ambulances rushed to Hurriya (Freedom) Square, where the Taiz protesters have camped out for days.
Protesters blamed the government, saying it was behind the attack, but said they would not retreat from the square.
At least 10,000 protesters were gathered in Hurriya Square, and similar numbers of Saleh loyalists were rallying in downtown Taiz.
It was the eighth straight day of protests in Yemen inspired by uprisings in Egypt and Tunisia.
Saleh, a U.S. ally against a Yemen-based al-Qaida wing that has launched attacks at home and abroad, is struggling to end month-old protests across the impoverished country that are now erupting on a daily basis.
The government, which receives millions of dollars in U.S. military aid, has allowed American drone strikes on al-Qaida targets and has stepped up counterterrorism cooperation.
His cash-strapped government is also trying to defuse a southern separatist revolt and maintain a shaky truce with northern Shiite rebels in the Arabian Peninsula state.
In a sop to protesters, Saleh has promised to step down when his term ends in 2013 and not hand power to his son.
Opposition groups said they are suspicious of Saleh's offer, however, and want concrete proposals for change.
A coalition of opposition parties, which had laid on rallies that drew tens of thousands, has now agreed to talk to him, but smaller, more spontaneous protests have continued, organized by students and others using mobile text messages and Facebook.
Yemen is the poorest Arab country, with nearly half the population living below the poverty line of $2 a day and a government riddled with corruption. It also is plagued by shrinking water and oil resources and an inability to feed its people. Poverty and malnutrition are rampant in the country's rugged hinterlands.