A clash between Syrian forces and army defectors erupted Sunday in a suburb of the tightly held capital of Damascus, adding urgency just as the Arab League was extending an observers' mission that so far has failed to start the process of putting an end to long months of bloody violence.

The two events outlined how an uprising against President Bashar Assad that was dominated by mass popular protests at first is moving toward an armed conflict that could draw international intervention — an outcome the Arab League is trying to avoid.

Arab League foreign ministers, meeting in Cairo, extended the much-criticized observers mission for another month, officials from the 22-member organization said.

The League decided to add more observers and provide them with additional resources, the officials said.

The officials, who spoke on condition of anonymity because they weren't authorized to speak to reporters, said the U.N. would train the observers.

The observer mission is supposed to be the first step toward implementing an Arab League plan to end the Syria crisis. Other points are pulling heavy Syrian weapons out of cities, stopping attacks on protesters, opening talks with the opposition and allowing foreign human rights workers and journalists in.

"There is partial progress in the implementation of the promises," Arab League chief Nabil Elaraby said in Cairo about Syria's implementation of the plan. Syria "did not carry out all its promises, although there are some implementation of pledges."

He added that the use of "extreme force" by Syrian forces have led to a reaction by the opposition "in what could lead to civil war."

So far the mission has not gone well. Though some credit it with tamping down violence in some places, the Local Coordination Committees activist group said Sunday that 976 people, including 54 children and 28 women, have been killed since the observers began their mission last month.

The New York-based Human Rights Watch called on the Arab League to "maximize" the effectiveness of the mission of the observers in Syria "to stop the killings."

"The deployment of the observers, has been disappointing ... Assad played games with observers," by moving around forces instead of removing them from cities, while the killing continues, Kenneth Roth, the executive director of Human Rights Watch, said in a statement.

The Arab League faced three options Sunday: ending the mission and giving up its initiative, extending it, or turning the crisis over to the U.N. Security Council, as some opposition groups have urged. There, however, it would face a possible stalemate because of disagreements among permanent members over how far to go in forcing Assad's hand.

The mission's one-month mandate technically expired on Thursday.

The pullout of Assad's security forces from the Damascus suburb of Douma marked the second time in a week that troops have redeployed from an area near the tightly-controlled Syrian capital, an indication that Assad might be losing some control.

Diplomacy has taken on urgency as opponents of Assad's regime and soldiers who switched sides increasingly take up arms and fight back against government forces.

The British-based Syrian Observatory for Human Rights' head Rami Abdul-Rahman said government troops had pulled back early Sunday to a provincial headquarters and a security agency building in the Damascus suburb of Douma after hours of clashes, although they still controlled the entrances. The clashes broke out after Syrian troops opened fire at a funeral on Saturday.

On Sunday afternoon, the battles resumed between the defectors and troops loyal to Assad, according to the Observatory and the Local Coordination Committees, another activist group. The LCC said that heavy machine gun fire was used in the clashes. They had no word on casualties.

Abdul-Rahman had no information on casualties from the clashes but said security forces at an entrance checkpoint shot dead one man who was passing by on Sunday. He added that one person was shot dead in a nearby town of Rankous as well as another person in the northwestern province of Idlib.

State-run news agency SANA said gunmen opened fire at the car of an army brigadier general, killing him and another army officers who was in the vehicle.

Syria-based activist Mustafa Osso confirmed that security forces had abandoned Douma.

A video posted by activists on social media showed five masked gunmen, one of them in uniform, who read a statement saying, "the city of Douma has been liberated from Assad's gangs." He warned Syrian troops not to try enter Douma or defectors would "fire rockets at the presidential palace" in Damascus and execute five prisoners they are holding.

The Associated Press could not verify the authenticity of the video.

Central Damascus has for most of Syria's 10-month uprising been under the tight control of forces loyal to Assad, but there have been intense anti-regime protests in its suburbs.

Last week, army defectors took control of the mountain town of Zabadani on the western edge of the capital, near the border with Lebanon. Army defectors control all its entrances.

The uprising in Syria is the most serious challenge to Assad, who took over from his father in 2000. The U.N. estimates some 5,400 have been killed since it began in March.

Also Sunday, state-run SANA, said an estimated 5,255 Syrian prisoners have been released over the past week under an amnesty, raising the total freed since November to more than 9,000. Opposition groups say thousands are still being held.

The U.S. has imposed sanctions on Syria as the bloodshed escalates. The U.S. has long called for Assad to step down, and officials say his regime's demise is inevitable.

Two U.S. Senators plan to introduce a bill to stiffen the sanctions.

The bill, sponsored by Democratic Senators Charles Schumer and Kirsten Gillibrand of New York would require President Barack Obama to identify violators of human rights in Syria, call for reform and offer protection to pro-democracy demonstrators. It would also block financial aid and property transactions in the United States involving Syrian leaders involved in the crackdown.