The Arab League sought help from the United Nations to address the escalating crisis in Syria on Tuesday, amid Syrian defiance of Arab efforts to broker a peace settlement and an upsurge of violence in which dozens of people died.

Gulf Arab countries pulled out of an Arab League monitoring mission, saying it was ineffectual, further casting into doubt the fate of an initiative aimed at ending the Syrian government’s use of force to suppress a 10-month-old revolt against President Bashar al-Assad’s rule.

Activist groups reported the deaths of at least 38 people, most of them in the flash-point city of Homs, as the government responded to the growing international pressure by stepping up its attempts to crush the revolt.

Syria’s foreign minister, Walid al-Moualem, said at a news conference in Damascus that Syria felt justified in escalating the use of force against protesters because a report by the Arab observer team acknowledged that some of them have taken up arms.

He signaled that the crackdown would intensify, saying there could be no reforms in Syria until the revolt had been suppressed.

“It is the duty of the Syrian government to take the necessary measures to address the problem of those armed elements who are wreaking havoc throughout Syria,” Moualem said. “The Syrian government must quickly take the situation in hand to preserve stability.”

Activists said a renewed crackdown appeared to be already underway. In Homs, at least 25 people were killed in shelling by security forces of two neighborhoods, said Homs activist Omar Shakir, who said at least three buildings collapsed. The Local Coordination Committees said 41 people were killed in Homs and 19 elsewhere in the country, including five defected soldiers.

“They are starting a new offensive, and I think in the coming days we will see a lot of blood,” Shakir said.

Opposition groups said they feared that a fresh assault is also being prepared against the city of Hama, the focus of a brutal crackdown last summer. The Syrian Revolution General Commission said that Internet connections, land lines and cellphone service had been cut and that tanks had gathered on the edges of the city.

The state news agency SANA reported that funerals were held Tuesday for 14 members of the security forces and two civilians killed the previous day in attacks by “armed terrorist groups.”

On Sunday, the Arab League cited Syria’s failure to stop the violence in its presentation of a transition plan that called for Assad to step aside, warning that the league would seek U.N. help if he did not comply.

On Tuesday, Arab League Secretary General Nabil Elaraby and Qatari Prime Minister Hamad Bin Jasim al-Thani wrote to U.N. Secretary General Ban Ki-moon requesting a meeting of the Security Council to address ways that it could help implement the plan.

Earlier, the six nations of the Gulf Cooperation Council — Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and United Arab Emirates — announced the withdrawal of their observers from the Arab League’s monitoring mission in Syria and urged the Security Council to take “all needed measures” to stop the violence, suggesting that they would be willing to countenance military intervention.

U.S. and European efforts to spur Security Council action have been blocked, however, by Russia, which remains staunchly opposed to any U.N. action that could open the door to international intervention in Syria.

The GCC withdrawal also pointed to Arab divisions over how to deal with the Syria crisis.

The Arab League announced that the monitoring mission would continue for another month, and the Syrian government said it had agreed to allow the monitors to stay. But the mission’s efficacy will probably be undermined by the absence of the powerful Arab Gulf states, which have been at the forefront of the Arab effort to put pressure on Assad.