GENEVA (AP) — Intensified fighting between Syrian government forces and rebels north of Aleppo has completely cut off access for humanitarian aid deliveries into the rebel-held part of the contested city, a U.N. spokeswoman said Tuesday.
Alessandra Vellucci told reporters that the passageway known as the Castello road, which is considered the only access in and out of eastern Aleppo, has been rendered "impassable" since hostilities there worsened starting Thursday.
Russian Foreign Minister Sergey Lavrov meanwhile expressed concern that the U.N.'s Syria envoy was "shirking his responsibilities" to reconvene stalled peace talks.
Lavrov said U.N. envoy Staffan de Mistura was apparently waiting for Washington and Moscow to agree on a political transition before reconvening indirect talks between the Syrian government and the opposition that last broke down in April.
"This is not the right approach," Lavrov said during a visit to Azerbaijan.
Lavrov said he was hoping to work out a common approach with U.S. Secretary of State John Kerry during his visit to Moscow later this week based on a U.N. Security Council resolution aimed at ending the five-year war. "On this basis we will then work with Staffan de Mistura so that he conscientiously fulfills his obligations," Lavrov said.
Russia, a key ally of Syrian President Bashar Assad, has in recent months worked with the United States, which supports the rebels, to try and secure a cease-fire leading to a political transition, with no success.
De Mistura's office declined to comment. He has set a target date of Aug. 1 to restart talks, but said conditions need to be ripe for progress toward political transition in Syria — what he has called the "mother of all issues." He has said that behind-the-scenes diplomacy has been continuing.
The fighting has meanwhile intensified in Aleppo, with rebels shelling government districts and warplanes striking rebel-held areas. Amid the heavy fighting, government forces were able to effective cut off the Castello road, raising fears of a new humanitarian crisis. The U.N. estimates that 300,000 people depend on Castello road.
"We continue to receive distressing reports of aerial bombardment and shelling on civilian locations in both western and eastern Aleppo city," said Vellucci, the U.N. spokeswoman. She urged the parties "to take all measures to protect civilians and facilitate humanitarian access to all civilians living in Aleppo city, as required under international humanitarian law."
Once Syria's commercial center, Aleppo has been bitterly contested since the summer of 2012. The latest fighting came despite a unilateral cease-fire declared by the Syrian military last week, which was later extended to Thursday.
A Turkey-based Syrian opposition figure, Osama Taljo, warned on Tuesday at a press conference in Istanbul that the vast majority of those who are now encircled in Aleppo are civilians, mostly women and children.
"The rebels have numerous ways of getting supplies and improvising roads but those at risk are the women and children. This is why we need the international community to take action," he said, speaking on behalf of various opposition factions in Aleppo.
Taljo derided the government's declared cease-fires, which he said are a cover for military assaults. "The cessation of hostilities means an escalation in hostile acts by the regime," he told reporters.
As government forces closed the Castello road, rebels hit back with an offensive on government-held districts Monday. The rebel shelling and ensuing clashes were some of the most intense yet near the old quarter and the city's famed citadel.
Elsewhere in Syria, opposition activists said an air raid struck refugee tents in a remote area near the Jordanian border, killing several people and wounding dozens.
Ahmad al-Masalmeh, an activist in Syria's southern province of Daraa, said seven Russian airstrikes targeted the tents in the Northern Hammad area, killing eight people and wounding 50. He said the tents are in a remote desert area where there is no cellphone coverage and that it's difficult for ambulances to reach the area.
The Britain-based Syrian Observatory for Human Rights, which monitors the war through a network of activists on the ground, said airstrikes believed to be Russian struck the encampment, killing at least three people and wounding many others.
Rami Abdurrahman, director of the group, said the casualties were most likely families of a rebel group known as the Eastern Lions, which fights the Islamic State group and is allied with the U.S.-backed New Syrian Army group. Last month, Washington accused Russian aircraft of bombing the New Syrian Army rebels near the Iraqi border.
The Local Coordination Committees, another opposition activist group, said seven Russian airstrikes on a camp housing the families of Eastern Lions fighters caused many casualties.
Younes al-Salameh, a spokesman for the Eastern Lions, said two jets attacked the al-Badayeh camp housing families who fled from northeastern Syria. He said an elderly man and two children were killed.
Associated Press writers Dominique Soguel in Istanbul, Aida Sultanova in Baku, Azerbaijan, Bassem Mroue and Zeina Karam in Beirut, and Sam McNeil in Amman, Jordan, contributed to this report.