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Syria accepted an Arab League proposal Wednesday calling for it to withdraw armored vehicles from the streets and stop violence against protesters in a bid to end the country's seven-month-old political crisis, an agreement that was met with deep skepticism by Syria's opposition.

Qatar's Foreign Minister Hamad bin Jassim urged Damascus to follow through with action on the ground amid concern that Syria has continued its bloody crackdown on anti-government protesters despite international condemnation and previous promises of reform.

Najib al-Ghadban, a U.S.-based Syrian activist and member of the opposition Syrian National Council, said implementation of the initiative would mean the end of the regime and President Bashar Assad was not likely to let that happen.

"What happened today is an attempt to buy more time," al-Ghadban told The Associated Press. "This regime is notorious for maneuvering and for giving promises and not implementing any of them."

In the latest violence, machine-gun fire and explosions erupted inside a city at the heart of Syria's uprising as activists reported two grisly attacks that killed at least 20 people in the past 24 hours, although it was not clear who was behind the attacks.

The Arab League efforts reflect the group's eagerness to avoid seeing another Arab leader toppled violently and dragged through the streets, as was slain Libyan strongman Muammar Qaddafi last month. An Arab League decision had paved the way for NATO airstrikes that eventually brought down Qaddafi.

Syria agreed to withdraw all tanks and armored vehicles from the streets, stop violence against protesters, release all political prisoners and begin a dialogue with the opposition within two weeks, according to the proposal. Syria also agreed to allow journalists, rights groups and Arab League representatives to monitor the situation in the country.

But it remains unclear if the agreement will make a difference on the ground. Activists on social networking sites called for massive marches across Syria to test the government's commitment to the Arab League plan, although they did not specify a date.

Dozens also protested outside the Arab League's Cairo headquarters as foreign ministers met Wednesday, waving the tri-colored Syrian flag and chanting slogans against Assad.

The proposal did not state where the dialogue between authorities and the opposition is to take place. Arab diplomats involved in the process said they had suggested Cairo while the Syrians insisted that all dialogue take place in the capital Damascus.

U.S. State Department spokeswoman Victoria Nuland said the Obama administration was waiting to see the details of the Arab League agreement with Syria. But she said Assad's government has a long track record of broken pledges.

"We're not going to judge them by their words. We're going to judge them by their actions," she told reporters in Washington. "There is a risk here that they are trying to string out diplomacy, that they are trying to offer their own people half steps or quarter measures rather than taking the real steps."

Syria blames the violence on "armed gangs" and extremists seeking to destabilize the regime in line with a foreign agenda, an assertion that raised questions about its willingness to cease all forms of violence. Previous attempts to hold dialogue with the opposition were unsuccessful.

"We are happy to have reached the agreement and we'll be happier if it is carried out," bin Jassim said. "Now it is important for the Syrian side to carry out this agreement because it is what will allow the situation to quiet down and the crisis to be resolved."

"We hope that there will be serious follow-through, whether regarding violence and killing or regarding prisoners," he said.

Hassan Abdul-Azim, a prominent Syria-based dissident who heads the National Committee for Democratic Change, welcomed the Arab League's efforts to solve the crisis in Syria but said dialogue was absolutely rejected as long as the current crackdown continued.

"We will wait and see the response to the initiative before deciding on the next steps in coordination with the opposition abroad and the youth on the ground," he said.

Regime opponents in Syria are a diverse, fragmented group and the opposition is struggling to overcome infighting and inexperience.

While the Syrian National Council says it will only negotiate the terms of a peaceful transfer of power, other opposition figures appear more willing to engage in dialogue with the regime. In accepting the initiative, Assad may be counting on that disunity to give the semblance of dialogue and gain time.

The proposal was presented by a council of Arab foreign ministers. Notably, Syrian Foreign Minster Walid al-Moallem did not attend the meeting. Instead, Syria's ambassador to Egypt and the Arab League, Youssef Ahmed, delivered Syria's response.

The U.N. says some 3,000 people have been killed since the revolt began in March.

U.N. Secretary General Ban Ki-moon said Wednesday he supported the agreement.

"I hope that this agreement will be implemented without delay," he told reporters in Tripoli, Libya, but noting that Assad has not kept past promises.

The fresh bloodshed, which apparently started late Tuesday in the city of Homs, which has endured the brunt of the government's brutal crackdown on dissent, suggests Syria is sliding toward chaos amid increasing signs that the crisis was exacerbating religious and sectarian tensions.

The Syrian opposition's two main activist groups said gunmen attacked factory workers in the Houla district on Wednesday, killing 11 people. Majd Amer, a local activist, said some of the men were decapitated and others shot in the head, their hands tied behind their backs.

Amateur videos posted online showed the men, bound and gagged, lying on the ground.

The killing spree amounted to a "massacre," said the activist groups, the British-based Syrian Observatory for Human Rights and the Local Coordination Committees activist network.

Amer and activist Mohammad Saleh in Homs said gunmen also attacked a bus carrying workers from the nearby village of Jib Abbas as they were returning from their jobs, killing nine passengers. They said the gunmen stopped the bus, released the women passengers, then killed the others.

The activists said the army brought in heavy reinforcements to the streets of Homs on Wednesday morning. Heavy machine-gun fire and explosions could be heard on the streets and residents said most people had stayed home because of the violence.

Syria has largely sealed off the country from foreign journalists and prevented independent reporting, making it difficult to confirm events on the ground. Key sources of information are amateur videos posted online, witness accounts and details gathered by activist groups.