The United Nations Security Council has called for an end to violence in Yemen, where forces loyal to President Ali Abdullah Saleh have attacked opposition protesters and clashed with defected soldiers loyal to the Yemeni people's revolution, leaving scores dead or injured.
The 15 Security Council nations, which include the US, China and Russia, issued a statement on Saturday calling on all sides to "reject violence, including against peaceful and unarmed civilians, and show maximum restraint."
At least 18 civilians and 11 defected soldiers were killed in Sanaa on Saturday, raising the death toll to 49 since President Saleh returned from a three month absence on Friday and 144 since pro-Saleh troops intensified the government's crackdown last Sunday.
The UNSC statement also "called on all parties to move forward urgently in an inclusive, orderly and Yemeni-led process of political transition".
"The members of the Security Council expressed their grave concern at the continued serious deterioration of the economic and humanitarian situation in Yemen. They were deeply concerned at the worsening security situation, including the threat from al-Qaeda in parts of Yemen," added the statement.
The council called for access to provide humanitarian assistance and called on all sides "not to target vital infrastructure."
Three people were killed and three others were wounded early Sunday in clashes in Yemen's second largest city Taiz, a tribal source said, amid an uneasy calm in the capital a day after deadly clashes.
The overnight fighting erupted between armed tribesmen who have thrown their support behind anti-government protesters and security forces loyal to embattled President Saleh.
On Saturday, government forces attacked unarmed demonstrators camped in Sanaa's "Change Square" and the headquarters of defected soldiers.
Troops loyal to Saleh launched the attack a little after midnight, opening fire with mortars and guns. Reports indicate that at least 18 people were killed and 54 injured in the assault.
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Muttahar al-Masri, Yemen's interior minister, however denied that a raid took place, blaming the gunfire on "extremists".
Snipers also targeted the people in the square from buildings around it, witnesses said.
Medics working at a field hospital set up in the square said that some of those killed were mangled.
"We have ... one killed in a terrible way by the mortar fire - we only have half a body," Dr Mohammed al-Qubati said.
Hundreds fled from the southern end of the camp, witnesses said, as the attack continued through the day.
Elsewhere in Sanaa, pro-Saleh forces shelled the headquarters of the First Armoured Division - the unit of defected soldiers supporting the Yemeni people's revolution.
Reports said 11 soldiers were killed and 120 injured in the shelling.
The main military rival of Saleh said the returning leader was set on driving the country into civil war and called on the international community to rein him in.
Major-General Ali Mohsen al-Ahmar issued a strongly worded statement on Saturday, calling Saleh a "sick, vengeful soul'' and comparing him to the Roman emperor Nero, burning down his own city.
|At least 54 protesters were injured on Saturday [Reuters]
Many Yemenis thought they had seen the last of Saleh when he flew to Saudi Arabia in June for medical treatment after a bomb explosion at his palace left him with severe burns.
His reappearance on Friday raised big questions over the future of the fractious Arabian Peninsula state.
In Washington, White House spokesman Jay Carney said: "We urge President Saleh to initiate a full transfer of power and arrange for presidential elections to be held before the end of then year.
"The Yemeni people have suffered enough and deserve a path towards a better future."
A senior Saudi official told AFP news agency that Saleh had returned from Riyadh to put his house "in order" and "prepare for elections".
Saleh will "leave" after this, the official said without specifying whether he would leave Yemen altogether or only leave power.
Yemen's wealthy Gulf neighbours have been trying for months to persuade Saleh to accept a plan under which he would hand over power in return for a promise of immunity from prosecution.
Saleh had been involved in the negotiations, repeatedly promising to step down only to change his position at the last minute.
"I return to the nation carrying the dove of peace and the olive branch," Saleh was quoted as saying by state television on Friday.
He also called for a ceasefire.
However, the violent crackdown on anti-Saleh protesters by pro-Saleh forces have left many Yemenis skeptical of his intentions.
Source: Al Jazeera and agencies