(CNN) -- Syrian officials and opposition activists blamed each other for an attack on a gas pipeline near the restive city of Homs on Tuesday, while opposition groups said more than 30 people had died in new clashes.
The London-based Syrian Observatory for Human Rights said three civilians were killed by government troops in Homs, while deserting government troops killed 18 members of the security forces in the city of Jasem. Syrian officials did not respond to CNN requests for comment on the incident, and state media did not mention it.
And the Local Coordination Committees of Syria, an opposition umbrella group, said police and troops still loyal to President Bashar al-Assad's government killed 11 people in and around Damascus, Hama and Homs, where the state-run Syrian Arab News Agency blamed the pipeline explosion on a "terrorist group."
CNN cannot independently confirm events inside Syria because the government restricts the activity of journalists. But activists in Homs said the government blew up the pipeline itself to distract Arab League monitors, who are in the country to try to protect civilians from violence at the hands of government security forces.
"The regime did that intentionally. They don't care about Homs; what difference does it make to them to have no power? We don't have any of the necessities: medication, heating fuel, food. And garbage is everywhere," said one activist.
Another activist in the city of Hama said the Arab League monitors there were surrounded by Syrian officials and security forces, making it difficult for locals to speak to the observers freely. The activist said the city still has many checkpoints and security forces with heavy machine guns, and that tanks have not been withdrawn from the city -- just hidden where monitors cannot see them.
The activists spoke to CNN by Skype from Syria. CNN is not naming them to protect their safety.
Top U.S. and French officials also expressed doubts about whether Syria was abiding by its November agreement with the Arab League, which calls for the release of protesters jailed by the months-long crackdown on anti-government demonstrations and the withdrawal of Syrian troops from cities. White House spokesman Jay Carney said Damascus was clearly breaking its deal with its fellow Arab states.
"Across the country, the Syrian people continue to suffer at the hand of the Assad regime, as indiscriminate killing of scores of civilians continues," Carney said. He said it was "past time" for the U.N. Security Council to take action, and said Washington was working with its allies "to increase the pressure on the Assad regime."
And U.S. State Department spokeswoman Victoria Nuland said that while some prisoners have been freed, the releases are "nothing like what the Syrian government promised to the Arab League."
"Our concern is that the Arab League monitors, although they are providing some ability for some demonstrators to express their views in some places, they have not led to the full implementation of the commitments that the Assad regime took on," Nuland told reporters in Washington. Meanwhile, she urged Syrian opposition forces to avoid attacks that would play into the government's hands.
"That's exactly what the regime wants, is to make Syria more violent and have an excuse to retaliate itself," Nuland said.
In Paris, French Foreign Minister Alain Juppe told France's I-Tele on Tuesday that he was "a little skeptical" about whether the monitors are getting free access to the facts.
"We await their report that will be carried out in the coming days," Juppe said. But he added, "I do not consider the battle already lost."
"The secretary-general of the Arab League has expressed the will to get to the bottom of this investigation," he said. "The truth must be established, and the regime cannot poison the observers who are on the ground."
French President Nicolas Sarkozy said Tuesday that President Bashar al-Assad must relinquish power, saying the "massacres" by his forces "evoke disgust and revolt in the Arab world, in France, in Europe and everywhere in the world." Sarkozy said nations must continue "unrelentingly denouncing a barbaric repression and ensuring that the observers from the Arab league have the means and the freedom to carry out their work correctly."
Arab League Secretary-General Nabil el-Araby is scheduled to discuss the monitoring team's preliminary report on Saturday, an official with the organization told CNN on condition of anonymity. El-Araby is scheduled to meet with the head of the Arab Human Rights Council on Wednesday, said the official, who is not authorized to speak to the press and asked not to be named.
El-Araby said Monday that the killing was still going on despite the presence of his observers.
"There is still gunfire, there are still snipers, and we hope that all that will disappear," he said in Cairo, adding: "There is gunfire from various directions, which makes it hard to tell who is shooting. There is no doubt that killing is ongoing, but I can't pinpoint the numbers."
Arab League observers entered Syria last week after the United Nations estimated that 5,000 people had been killed since March in an uprising against the government.
Al-Assad's government says it is cracking down on armed terrorists.
The Arab League aims "to provide protection to Syrian civilians," el-Araby said Monday, adding that it was asking for a cease-fire and for the names of detainees in Syrian prisons. Nearly 3,500 prisoners have been freed, he said.
The Arab League has placed more than 70 monitors in six cities, and the number of observers soon will exceed 100, el-Araby said.
CNN's Amir Ahmed, Hamdi Alkhshali, Arwa Damon, Saskya Vandoorne and Alexander Felton contributed to this report.