BEIRUT — A second round of Syrian peace talks started acrimoniously in Geneva on Monday as the two sides traded accusations over disruptions to humanitarian operations in the city of Homs and allegations of mass killings in nearby Hama.
The Syrian government accused Islamist rebel battalions of a massacre of civilians in a village in central Hama province over the weekend. Hama is largely home to Alawites, members of the same sect as President Bashar Assad. Activists said most of the dead were progovernment fighters.
Aid operations in Homs, which were approved in a confidence-building measure between the government and opposition in initial talks last month, have been plagued by violence. Both sides have blamed each other for violations of the cease-fire.
Still, the truce was extended for three more days and about 460 civilians were evacuated Monday, according to Syrian officials, bringing the total evacuated since Friday to more than 1,000.
The shelling and gunfire targeting humanitarian workers attempting to reach rebel-held areas of Homs are reminders of the complexities of reaching even the smallest concessions in a civil war where developments on the ground have consistently outpaced diplomacy.
Battle lines are constantly shifting, with the Al Qaeda-inspired Islamic State of Iraq and Syria withdrawing from its bases in oil-rich Deir Ezzor on Monday after rebel infighting.
Representatives from the rebels and the government did not meet face-to-face on Monday. Instead, UN mediator Lakhdar Brahimi held separate sessions with each delegation. With tensions high in Geneva, there are no plans for the two sides to sit in the same room Tuesday either.
Opposition spokesman Louay al-Safi squarely charged the government with attacks on aid workers in Homs and the deaths of at least three civilians.
‘‘The negotiations cannot continue while the regime is stepping up its violence against the Syrian people,’’ he told reporters after his meeting with Brahimi.
The government meanwhile blamed ‘‘terrorists’’ for the disruption.
‘‘How can we shoot at ourselves?’’ said the Syrian deputy foreign minister, Faisal Mekdad. ‘‘This is ridiculous.’’
There have been disagreements over the agenda of the Geneva meeting, with the Syrian government insisting that talks focus on ending terrorism, while the opposition is eager to move onto the core issue of political transition. Issues including prisoner exchange and humanitarian access are likely to be discussed on the sidelines, diplomats said.
‘‘If terrorism does not stop in Syria, it will spread to neighboring countries and all the countries of the world,’’ Mekdad told reporters. ‘‘This is the main menace to peace in Syria.’’
Syria said it had submitted to the United Nations a draft statement condemning killings in the progovernment village of Maan in Hama. It requested an ‘‘immediate and very clear condemnation’’ from Brahimi.
Syrian state news agency SANA said the dead included 42 women and children. But the Syrian Observatory for Human Rights said 25 people were killed, mostly fighters with the National Defense Force, a progovernment paramilitary group.
Islamist brigades Ahrar al Sham and Jund al-Aqsar were among rebel groups that claimed to have ‘‘liberated’’ the village. Videos posted online showed rebels pulling down the state flag. One showed a slain man in military fatigues.
Western diplomats are pressing for more rebel groups to engage with the Geneva process, amid questions about the point of talks with an external opposition that has little power over the fighters within Syria.
Rebels are also racked by infighting as they attempt to oust fighters from ISIS, which even Al Qaeda has disowned.
Al Qaeda’s local affiliate, Jabhat al-Nusra, is among the rebel groups that ousted ISIS from Deir Ezzor, an indication of ISIS’s growing isolation. In a statement on Sunday, ISIS accused Nusra of having ‘‘stepped away from the road of the righteous.’’ The Syrian Observatory said ISIS had pulled out after Nusra refused its requests for mediation.
UN humanitarian chief Valerie Amos sharply criticized both the government and the opposition on Monday, saying UN and Syrian Red Crescent workers were ‘‘deliberately targeted.’’
Many of the civilians evacuated since Friday ‘‘were traumatized and weak,’’ the Associated Press quoted Amos as saying. They described ‘‘terrible conditions at the field hospital in the Old City, where the equipment is basic, there are no medicines, and people are in urgent need of medical attention,’’ she said.
Under the UN-brokered truce, the government refused to allow males between the ages of 15 and 55 to leave, presuming them to be fighters. Those leaving are women, children, and the elderly.
No details have emerged of the attempts to get the parties to implement their agreements on cease-fires, prisoner exchanges, or better access for aid agencies.