GENEVA/BEIRUT: Syrian government forces Tuesday called on opposition fighters in Aleppo to drop their weapons and surrender to authorities as they captured new ground on the northwestern edge of the city, tightening the siege on rebel-held parts of the metropolis where some 300,000 people live, activists said.

The push in which troops captured large parts of the city’s Lairamoun area came as state TV reported that the General Army Command informed residents of rebel-held parts of Aleppo via cellphone text messages that the army has created several safe passages and makeshift centers for whoever wants to leave those areas.

The military warning comes days after the army fully encircled Aleppo, setting the stage for a prolonged siege aimed at eventually forcing the surrender of rebels holed up in the eastern parts of the city. 

Dozens of people have been killed in the past few weeks amid intense fighting. Grim scenes of people trapped under the rubble of buildings have emerged and food shortages have been reported.

“Some people were waiting for a breakthrough but now they are all living in horror because of the incessant bombing. People’s state of mind is: If we don’t die in an airstrike, we will die from the siege,” Manal Daaboul, an Aleppo activist, told The Daily Star.

In Geneva, the U.N. envoy for Syria said he aims to call a new round of talks between government and opposition envoys in Geneva “toward the end of August.”

Staffan de Mistura said he wants to see the outcome of steps agreed upon in Moscow last week between the United States and Russia, in order “to make these talks particularly fruitful and hopeful” before setting a precise date.

The U.N. envoy spoke to reporters Tuesday after a closed-door meeting in Geneva with high-level U.S. and Russian diplomats. He said the discussion centered on initiatives about the “urgent need” for progress on issues like a widely violated cessation of hostilities, humanitarian access, counterterrorism and political transition in Syria.

Syrian government forces and their allies have been on the offensive around Aleppo, Syria’s largest city, for weeks.

The army Tuesday said it would keep providing residents with basic necessities, but called all those living in rebel-held parts of the city to kick out “mercenaries and foreign fighters.”Baraa al-Halabi, an opposition activist in Aleppo, described the army claim about safe passages as “nonsense” and said he was not aware of any telephone messages sent to residents.

The Lebanese group Hezbollah’s Al-Manar TV aired footage of government forces pushing in what appeared to be an industrial area near Aleppo. The station confirmed that President Bashar Assad’s forces capture of areas in Lairamoun and near Castello Road, the main link between rebel-held parts of Aleppo and the rest of the country.

In other developments, regime forces freed 14 members of the army and allied fighters who being held in captivity by Nusra Front in the town of Sayda, situated in Deraa countryside, according to the Britain-based Syrian Observatory for Human Rights. 

Earlier Tuesday, Russian Foreign Minister Sergey Lavrov said that recent U.S.-Russia discussions should encourage moderate Syrian opposition groups to leave areas occupied by Al-Qaeda’s branch in Syria, thus helping to implement a truce. Lavrov spoke to Russian news agencies after talks in Laos with U.S. Secretary of State John Kerry, who visited Moscow earlier this month.

Moscow and Washington have differed over the role of the local Al-Qaeda branch known as the Nusra Front, with Russia calling the group terrorists and the U.S. asking Russia not to target them for fear of hitting the moderate opposition. The U.S. has offered Russia a military partnership in Syria that includes intelligence and targeting sharing and even joint bombing operations.

The proposal would address the Nusra Front, which has presented one of the most persistent obstacles in enforcing a cease-fire in Syria. The group is engaged in a variety of local alliances with other rebel groups the U.S. and its Arab allies want shielded by the cessation of hostilities. The Al-Qaeda affiliate’s fighters are often embedded with such groups on the battlefield or move between various militant formations.

The dispute over the Nusra Front has undermined the Russia- and U.S.-brokered truce with fighting continuing to rage in many areas in Syria. It has also fueled speculation of a potential split between Nusra and Al-Qaeda for practical purposes.

A Nusra Front official told the Associated Press Tuesday that the group’s leader Abu Mohammad al-Golani plans to announce a disassociation with Al-Qaeda soon. Speaking via text message from northern Syria, the official, who spoke on condition of anonymity because he was not authorized to speak publicly about the issue, said Nusra would merge with other insurgent groups.