BEIRUT (AP) ― Violence sweeping across Syria killed 25 people on Saturday, most of them in a battle between troops and a growing force of army defectors who have joined the movement to oust the autocratic president, activists said. The Arab League, meanwhile, agreed on the details of economic and diplomatic sanctions against the regime.

The revolt against Bashar Assad’s rule began with peaceful protests in mid-March, triggering a brutal crackdown. The unrest has steadily become bloodier as defectors and some civilians take up arms, prompting the United Nations’ human rights chief to refer to it this week as a civil war and urge the international community to protect Syrian civilians.

Sanctions by the United States, the European Union, Turkey and the 22-member Arab League have so far failed to blunt the turmoil, but are leaving Assad’s regime increasingly isolated.

Arab League ministers meeting in the Gulf nation of Qatar on Saturday to finalize the bloc’s penalties agreed on a list of 19 Syrian officials subject to a travel ban. Among them are cabinet ministers, intelligence chiefs and security officers, but the list does not include Assad.

Many of the Arab sanctions, which were first announced last Sunday, went into effect immediately, including cutting off transactions with the Syrian central bank, halting Arab government funding for projects in Syria and freezing government assets. Flights between Syria and its Arab neighbors will stop Dec. 15.

The Arab League also agreed to ban the supply of all weapons to Syria.

The worst violence on Saturday took place in the restive northwestern city of Idlib.

The pre-dawn clashes between regime forces and defectors killed seven soldiers and policemen, as well as five defectors and three civilians, according to a British-based group of Syrian activists called the Syrian Observatory for Human Rights.

Elsewhere, security forces killed one civilian in the southern province of Daraa, six in the central region of Homs and three others in areas near Idlib, the observatory said.

The U.N.’s top human rights official said this week that Syria is in a state of civil war and that more than 4,000 people have been killed since March.

Until recently, most of the bloodshed in Syria was caused by security forces firing on mainly peaceful protesters, but there have been growing reports of army defectors and armed civilians fighting regime forces.

November was the deadliest month of the uprising, with at least 950 people killed in gunbattles, raids and other violence, according to activist groups.

In the west of the country, Syrian troops detained at least 27 people in the village of Talkalakh on the border with Lebanon and set fire to the homes of nine activists who were on the run, the observatory said.

Talkalakh is within walking distance from Lebanon, and at least two Lebanese civilians were struck by bullets on their side of the border on Friday. Witnesses said that they had heard hours of explosions and heavy machine-gun fire coming from the village.

The country’s state-run SANA news agency confirmed the arrests in Talkalakh, saying that those detained were “terrorists” involved in smuggling weapons, drugs and bringing in fighters from Lebanon. The regime has consistently blamed armed gangs acting out a foreign conspiracy for Syria’s unrest.

The opposition activists reject that and say they are pushing for Assad’s ouster in hopes of breaking open the nation’s closed political scene.

The reports of new violence could not be independently confirmed. The regime has sealed the country off from foreign journalists and prevented independent reporting.

Syria has refused to accept an Arab League proposal for ending the violence under which a team of Arab monitors would enter the country to ensure the government has halted its crackdown on protesters.

Arab League officials at Saturday’s meeting in Qatar said Syria has asked for a meeting to discuss the proposed monitoring team with the league’s secretary-general, Nabil Elaraby. But no date or venue for those talks was announced.

The league suspended Syria’s membership in November.