Syria faced renewed international pressure Sunday as the Arab League said it would meet this week to consider new moves against the country, after a deadline for the government to end a crackdown on protesters and admit international monitors expired Saturday.

The group of Arab states on Sunday rejected Syria’s request for modifications to a proposed program for monitors to enter the country, saying the request would “change the nature of the mission” of the monitors. The Arab League said it planned to meet Thursday to discuss measures, which could include heavy sanctions and Syria’s exclusion from the league.

The announcement came as reports emerged of an attack on the ruling Baath Party headquarters in central Damascus, the first such strike within the Syrian capital and the latest in a series of attacks indicating that some members of the uprising against the government may have turned to violence.

Syrian Foreign Minister Walid al-Moualem, speaking at a news conference in Damascus, called the Arab League’s deadline unimportant and said he would send further questions to the group’s chief, Nabil Elaraby, before deciding whether to agree to its demands.

Moualem was dismissive of international pressure, saying the Arab League, in its condemnations of the government of President Bashar al-Assad, was ignoring the presence of armed gangs operating in the restive city of Homs and threatening the sovereignty of Syria.

He added that comments by U.S. Secretary of State Hillary Rodham Clinton in Indonesia last week that “there could be a civil war with a very determined and well-armed and eventually well-financed opposition” were “wishful thinking.”

Citing Clinton’s remarks and Turkish officials’ increasingly strong line against Assad’s government, Moualem asserted that foreign powers were trying to incite sectarian conflict in Syria, where divides have grown among Christians, Sunni Muslims and Alawites, the minority group to which the ruling family belongs.

The strike Sunday on the Baath Party headquarters followed a high-profile attack Wednesday on an air intelligence base outside Damascus. Details of the Sunday attack were unclear.

According to Rami Abdelrahman of the London-based Syrian Observatory for Human Rights, people riding motorcycles attacked the building with grenades, hitting an external wall, and then launched two rocket-propelled grenades, which fell to the ground, before riding away.

However, a witness reported seeing a car from which machine guns were being fired. The Agence France-Presse news service sent a correspondent to the scene, but no signs of damage were reported.

The foremost organization conducting armed operations in the country is the Free Syrian Army, a group of defected military personnel, but a spokesman denied any involvement in the Sunday attack.

“The Baath Party headquarters and all its branches are owned by the Syrian people and not by the regime, and, therefore, we do not target them,” said Maher Naimi, alleging that Assad’s forces had conducted the attack, with the intention of implicating and discrediting the Free Syrian Army.

He added that the organization was still in defense mode but was planning to move to the “attack phase,” during which it could strike the presidential palace and other government institutions.

Assad, in an interview with the Sunday Times, condemned such armed groups, saying, “After eight months the picture is clear to us. . . . It is not a question of peaceful demonstrations but an armed operation.”

But on CNN’s “State of the Union,” former secretary of state Condoleezza Rice blamed the unrest squarely on Assad, saying he is “driving his country to the brink of civil war.”

“Syria is the handmaiden of the Iranians throughout the region,” Rice said on the Sunday news show. “And so the fall of Bashar al-Assad would be a great thing, not just for the Syrian people — that’s first and foremost — but also for the policies of the United States and those who want a more peaceful Middle East.”