Deadly fighting spread across Yemen's capital on Thursday as tribesmen joined battles between rival military units, raising fears among frightened residents the country is descending into civil war.
The soaring tensions between troops loyal to Yemeni President Ali Abdullah Saleh and opponents of his regime collapsed efforts on Wednesday by international mediators to promote a Gulf-initiated peace deal aimeed at halting the political impasse that has gripped Yemen for months.
At least four civilians were killed when they were caught in the crossfire of the fighting that broke out early Thursday between Republican Guard troops commanded by Saleh's son Ahmed, and dissidents loyal to General Ali Mohsen al-Ahmar, witnesses and medics said.
They said two women and a man were shot by snipers positioned on rooftops near and overlooking Change Square, the base of the anti-government protesters.
Another man died from wounds sustained when a mortar shell smashed into the square. Nine people were also wounded in the blast and several tents set up by protesters caught fire, according to witnesses.
Thursday's deaths bring the toll since Sunday to 89. Medics said hundreds had been wounded, adding that most of the casualties were civilians caught in the crossfire or gunned down by Saleh loyalists.
"I can no longer open my store for fear of stray bullets, whether from the opposition or government forces. Every day there are many casualties due to the stray bullets," said 25-year-old Mohammed al-Jabiri, who owns a mobile phone shop in Sanaa.
Fighting which had been concentrated since Sunday in the city centre and at Change Square spread on Thursday to Sanaa's Al-Hasaba district, where gunmen loyal to powerful dissident tribal chief Sheikh Sadiq al-Ahmar traded fire with followers of Saghir bin Aziz, a tribesman loyal to Saleh, witnesses
Bin Aziz, who is from Yemen's most influential tribe Bakil, is also a Republican Guard officer and a member of parliament.
Witnesses said men loyal to Hemyar al-Ahmar, Sheikh Sadiq's brother, joined the battles and that shells were being fired from the building of Yemen's interior ministry towards his house and that of another brother Hussein al-Ahmar.
There was no indication of casualties from that fighting.
"The city is empty. Schools, banks and businesses are shut as the ghost of war looms over Sanaa," one resident told AFP.
Another resident, who has been holed up in his home for days, said life had become unbearable.
"My children haven't slept in a week. They have nightmares every night from the shooting and the explosions," said Amin al-Faqih, 42, a father of three.
"My children beg me every day to take them to a place far far away from here, away from the nightly explosions and gunfire," he said.
Commuters said government forces have closed all entrances to the capital, with no cars allowed in or out.
The soaring levels of violence have raised long standing fears that Yemen, which is facing a Shiite rebellion in the north and the growing influence of Al-Qaeda in the south in addition to a southern separatist movement, is slipping towards full blown civil war.
United Nations envoy Jamal Benomar told AFP late Wednesday that the deteriorating security situation, and the reluctance of both sides to reach a political resolution, raises "the risk of civil war breaking out."
Benomar arrived Tuesday in Yemen where he, and Gulf Cooperation Council chief Abdullatif al-Zayani had been working to broker a peace-deal between the warring parties.
Zayani left Yemen Wednesday after efforts to reach a political consensus failed, saying the parties were not ready to negotiate.
He is expected in New York on Friday to discuss the Yemeni crisis with GCC foreign ministers and international diplomats who are gathered at the UN for the annual General Assembly meeting, a
Yemeni diplomat said, requesting anonymity.
Protesters who had been camped in their thousands in Al-Zubairi Road since Sunday fled after the main boulevard in the centre of the capital turned into a battlefield Thursday, an AFP correspondent said.
Thousands however remained camped out at Change Square to the north of Al-Zubairi, guarded by Ahmar's dissident troops.
To the south, Saleh's security forces, and the Republican Guard troops are mostly in control, largely dividing the capital in two with Al-Zubairi serving as an increasingly bloodied demarcation line.
The latest wave of fighting broke out on Sunday when swarms of protesters marching from Change Square towards the city centre in a bid to extend their sit-in came under fire from Saleh's forces, prompting intervention from Ahmar's troops.
Zayani and Benomar had been hoping to convince the opposition and Saleh's government to sign the initiative, which calls on Saleh to step down and hand over all constitutional authorities to his deputy.
In return, Saleh and his family would be granted immunity from prosecution.
Saleh has been in Riyadh since he was wounded in a June attack on his palace compound in Sanaa.