Breaking News of Syrian clashes

√. UK says Syria now obliged to comply with peace plan
√. Free Syrian Army withdraws from Damascus district
√. Thousands of Iraqis evacuated from Syria
√. Assassinated ministers buried and a fourth confirmed dead

In a video posted online Sunday, the head of the rebel Free Syrian Army in Aleppo announced an operation "to liberate the city of Aleppo from the rule of the Assad thugs whose hands were blood stained by heinous crimes against our people.

Brig. Gen. Abdel Jabbar Al-Obeidi urged regime soldiers to defect or step aside and not fight against his men, with the promise that no one would be harmed.

He vowed to secure Aleppo and protect all minorities and sects, including the members of Alawite sect that the president belongs to.

Aleppo and the capital city of Damascus have been al-Assad strongholds. But heavy clashes in Damascus over the past week, along with recent bombing that killed four members of al-Assad's inner circle and government, suggest cracks in the regime's armor.

Fierce clashes broke out Sunday morning between regime and rebel forces in Aleppo, opposition activists said.

An entire building collapsed in Seif al-Dawla neighborhood after a regime tank ... targeted it with four shells,  the Local Coordination Committees of Syria said.

If rebels gain control of Aleppo, the commercial hub of Syria, it would mark a pivotal point in the Syrian crisis and deal a heavy blow to al-Assad's financial ties.

In May, a violent crackdown on a peaceful demonstration at Aleppo University was one of the turning points of the uprising, with anti-regime students and civilians shot in the streets.

After 16 months of daily bloodshed, the Syrian crisis now zeroes in on Aleppo, the country's most populated city and a critical one for both President Bashar al-Assad's regime and rebels.

Time Is Running Out in Syria: World Leaders

A world conference accepted a U.N.-brokered peace plan that calls for the creation of a transitional government in Syria, but at Russia's insistence the compromise agreement left the door open to Syria's president being part of it.

representatives of the five permanent members of the UN Security Council — China, France, Russia, the United Kingdom and the United States — along with Turkey, Kuwait, and Qatar, reached an agreement during a conference in Geneva that a transitional government should be set up in Syria, but the question of whether President Bashar al-Assad will step down was left undecided.

The U.S. backed away from insisting that the plan should explicitly call for President Bashar Assad to have no role in a new Syrian government, hoping the concession would encourage Russia to put greater pressure on its longtime ally to end the violent crackdown that the opposition says has claimed more than 14,000 lives.

The crisis talks were called by the Arab League and UN special envoy Kofi Annan, who told the press in his concluding remarks: “It is for the people to come to a political agreement but time is running out.

Syrian opposition figures immediately rejected any notion of sharing in a transition with Assad, though the agreement also requires security force chiefs and services to have the confidence of the people. Assad's government had no immediate reaction, but he has repeatedly said his government has a responsibility to eliminate terrorists and will not accept any non-Syrian model of governance.

U.S. Secretary of State Hillary Clinton insisted on Saturday that Assad would still have to go, saying it is now incumbent on Russia and China to show Assad the writing on the wall" and help force his departure.

President Bashar Assad “will still have to go, he will never pass the mutual consent test given the blood on his hands.

“It is now incumbent on Russia and China to show Assad the writing on the wall,” Clinton said.

Kofi Annan was appointed the special envoy in February, and in March he submitted a six-point peace plan that he said the Assad regime accepted. It led to the April 12 cease-fire agreement that failed to hold.

The U.N. plan calls for establishing a transitional government of national unity, with full executive powers, that could include members of Assad's government and the opposition and other groups. It would oversee the drafting of a new constitution and elections.

Annan said following the Geneva talks that "it is for the people of Syria to come to a political agreement.

The way things have been going thus far — we are not helping anyone,” Annan said, according to The Associated Press. “Let us break this trend and start being of some use.

Rami Abdul-Rahman, director of the Britain-based Syrian Observatory for Human Rights, said following the agreement that no member of the Syrian opposition will accept to be part of a transitional government while Assad is still in power.

"Assad's staying in power will mean the continuation of the bloodshed in Syria," he said.