DAMASCUS, Syria -- Syria's government accepted Tuesday a proposed U.S.-Russian cease-fire that is to go into effect later this week, reserving the right to respond to any violations of the truce, while the main opposition and rebel umbrella group approved the deal but set its own conditions for compliance.
The development followed an agreement between Washington and Moscow for a new cease-fire for Syria that would take effect on midnight Friday local time, even as major questions over enforcement of that truce remain unresolved.
Also, the truce will not cover the Islamic State group, Syria's al-Qaida-branch known as the Nusra Front, or any other militia designated as a terrorist organization by the U.N. Security Council.
But exactly where along Syria's complicated front lines the fighting would stop and where counterterrorism operations could continue under the truce is still to be addressed. In addition, the five-page plan released by the U.S. State Department leaves open how cease-fire breaches would be dealt with.
Syria's Foreign Ministry said it accepts the proposed truce but that its operations will continue against IS, al-Qaida's branch in Syria and "other terrorist groups." It also stresses the right of its armed forces "to retaliate against any violation carried out by these groups."
Cabinet minister Ali Haidar said the government will in principle respect the ceasefire, though he could not "speak on behalf of the armed groups."
"Violations will happen from other parties and not from the Syrian state's side," Haider told The Associated Press after talks in Damascus with Peter Maurer, the president of the International Committee of the Red Cross.
The main umbrella for Syrian opposition and rebel groups, the High Negotiations Committee, gave a conditional approval late Monday. The HNC said the "acceptance of the truce is conditional" on the government ending its siege of 18 rebel-held areas, releasing detainees and the halting of aerial and artillery bombardment.
However, Talal Sillo, a spokesman for the predominantly Kurdish Syria Democratic Forces told The Associated Press that his group will not abide by the truce because it's fighting against IS in northern Syria.
Also Tuesday, the Russian military said it has set up a coordination center to help enforce the cease-fire. Russian Defense Ministry spokesman Maj.-Gen. Igor Konashenkov said the center is located at Syria's Hemeimeem air base, which hosts Russian warplanes. He said the center was established in line with the U.S.-Russian agreement.
Its purpose, Konashenkov said, would be to help organize cease-fire negotiations between the Syrian government and the opposition. Russia has given out its hotline numbers for enforcing the truce to the United States, he added.
But some Syrians in the northern town of Qamishli expressed skepticism the truce would hold.
"If the international community had wanted to stop the bloodshed, the killing and shelling, this could have happened three or four years ago," Bakr Safir told the newsgathering Arab agency Arab24.
U.N. envoy Staffan de Mistura halted the latest Syria talks in Geneva on Feb. 3 because of major differences between the two sides, exacerbated by increased aerial bombings and a large-scale government military offensive under the cover of Russian airstrikes.
It was not immediately clear if de Mistura will set a new date for the resumption of the talks, initially scheduled to resume on Thursday. Last week, he was quoted by Swedish newspaper Svenska Dagbladet as saying the Syria talks won't resume in Geneva on Feb. 25 because he cannot "realistically" get the parties in the conflict back to the table by then.
Syria's state news agency SANA reported late Monday that a new humanitarian aid convoy made up of 44 trucks entered the besieged Damascus suburb of Moadamiyeh. The delivery was conducted under the supervision of the Syrian Arab Red Crescent and the United Nations, SANA said.
On Tuesday, state TV reported that aid entered another rebel-held suburb, Kfar Batna.
The U.N. humanitarian agency confirmed the delivery. Spokesman Jens Laerke of the U.N. Office for the Coordination of Humanitarian Affairs said the deliveries were "under way" to help some 20,000 people in Moadamiya and another 10,000 people in Kfar Batna.
The latest distribution of aid came as Maurer, the ICRC president, began a five-day visit to Syria — his fourth since taking office in 2012.
"This is a critical situation at the present moment with millions of people in need and the objective of course of this trip is to scale up our operations and to bring as good as we can more help to Syrian people," Maurer said.
In northern Syria, the IS on Tuesday captured the town of Khanaser, cutting supply lines for government forces between the northern city of Aleppo and central and western Syria.
The Britain-based Syrian Observatory for Human Rights says IS fighters captured Khanaser along with 12 surrounding hills. The Aamaq news agency, which is affiliated with the extremist group, also reported that IS was now in "full control" of the town, southeast of Aleppo.
The Observatory said 35 troops and 16 IS fighters were killed in the battles, adding that many were wounded.
The Observatory, which tracks Syria's civil war, said Tuesday that it has documented the death of 271,138 people since the country's crisis began five years ago. The activist group also said the real death toll is estimated to be about 100,000 higher than the figure it released, which the Observatory said was based on its lists of deceased people's names.
The United Nations, which last released a death toll figure for Syria several months ago, says the war has killed 250,000 people.
Mroue reported from Beirut. Associated Press writer Jamey Keaten contributed to this report from Geneva.