Deadly clashes killed eight people in the Yemeni capital as tension spiked following a new wave of killings of anti-regime protesters by troops loyal to veteran President Ali Abdullah Saleh.
Eight people were killed and 27 wounded in the overnight street battles, which saw tribes and troops opposing Saleh ranged against loyalists, medics and a tribal source said on Monday.
France condemned the use of force against protesters and urged respect for human rights.
"We condemn in the strongest terms the use of force against demonstrators and call on parties to exercise restraint... Violence should stop and the international law, mainly human rights, should be respected," said foreign ministry spokesman Bernard Valero.
Four of the dead in the overnight clashes were killed in shelling that targeted Change Square, where protesters demanding the ouster of Saleh have camped out for months, medics said.
Some 10 rockets struck around the square, including one close to a field clinic, a medic at the facility said.
Fierce clashes took place in the northern Sanaa neighbourhood of Al-Hassaba between tribesmen led by Sheikh Sadeq al-Ahmar, who opposes Saleh, and followers of Sheikh Saghir bin Aziz, who remains loyal to the embattled leader.
Bin Aziz's brother, Sheikh Saleh, 35, was killed when shrapnel penetrated his head, a medic at the Saudi German hospital said, adding that five others were wounded.
Two people killed in clashes in Al-Hassaba and one of the four killed in the shelling of Change Square were taken to the Science and Technology Hospital, Dr Mohammed al-Sarmi said.
He said the hospital also admitted 22 wounded.
A source in the office of Sheikh Sadeq, who leads the powerful Hashid tribal confederation, said a civilian was killed when a rocket hit his house in Bahrain Street, in Al-Hassaba.
On Monday, thousands of women held a protest close to the foreign ministry in Sanaa, where demonstrators were shot dead on Saturday.
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"Those who kill the youths of the revolution and peaceful demonstrators should be executed," said a banner carried by the protesters.
In Yemen's second-largest city Taez, tens of thousands of women demonstrated to condemn the killing of Aziza Ghaleb, 21, who on Sunday became the first woman to be killed since anti-Saleh protests erupted in January.
Saleh on Sunday charged that the protests were being militarised and were part of a coup led by Islamists, apparently alluding to the Islah (Reform) party, Yemen's largest parliamentary opposition party.
Protesters said Saleh's forces were trying through the shelling to force them to leave Change Square.
"The shelling came after Saleh's speech. He is trying to terrify us to force demonstrators to go home, but they will not before achieving all their goals by bringing down the regime," leading protester Walid al-Ammari told AFP.
Clashes also broke out overnight in Ziraa Street, east of Change Square, between troops from the dissident First Armoured Division, led by General Ali Mohsen al-Ahmar, which provides protection for protesters, and Central Security forces loyal to Saleh.
Tension had escalated in Sanaa after demonstrators raised the stakes on Saturday, marching towards zones of the capital controlled by Saleh's forces, prompting a deadly response from loyalist troops and gunmen.
Saleh's forces shot dead 12 protesters on Saturday, while six people, including four demonstrators and two soldiers of Ahmar's division, were killed on Sunday, according to medics. Dozens more were wounded.
Ahmar's First Armoured Division said it lost 10 soldiers, including a major, in gunfire from Saleh loyalists over the past two days.
It accused the elite Republican Guard, commanded by Saleh's son Ahmed, and other security bodies led by relatives of the veteran leader of being behind the killings, along with loyalist "thugs."
"This was part of the series of crimes committed by Saleh and his bloody gang against peaceful demonstrators and their guards of the soldiers of the free Yemeni army that backs the revolution," it said in a statement.
General Ahmar has called on the international community to take immediate action to stop the bloodshed and force Saleh to step down.
Despite mounting pressure from Western governments as well as the six-nation Gulf Cooperation Council, Saleh has for months refused to sign a deal brokered by the GCC for him to hand over power in return for promise of immunity from prosecution.
According to a letter from Yemen's youth movement sent to the United Nations earlier this month, at least 861 people have been killed and 25,000 wounded since mass protests erupted across the country.