BEIRUT, Lebanon (AP) — Syria’s fragile ceasefire started to unravel yesterday with the first aerial attacks on rebel-held neighbourhoods of Aleppo and a southern village that killed at least eight people, violations that came as tensions between the American and Russian brokers of the deal worsened following a deadly US strike on Syrian government forces.

The air raid by the US-led coalition killed dozens of Syrian soldiers and led to a harsh verbal attack on Washington by Damascus and Moscow. The US military says it may have unintentionally struck Syrian troops while carrying out a raid against the Islamic State group in eastern Syria on Saturday.

The seven-day ceasefire is supposed to end at midnight, according to a Syrian army statement issued last week. The US and Russia have said that if it holds for seven days, it should be followed by the establishment of a Joint Implementation Center for both countries to coordinate the targeting of Islamic State and al-Qaeda-linked militants.

Despite largely holding, the ceasefire has been repeatedly violated by both sides, and aid convoys have not reached besieged rebel-held neighbourhoods of Aleppo, Syria’s largest city and one-time commercial centre, which has been the centre of violence in recent months. Aid delivery to Aleppo is part of the US-Russia ceasefire deal.

Earlier this month, Syrian government forces and their allies captured areas they lost south of the city, re-imposing a siege on its Opposition-held eastern neighbourhoods. More than 2,000 people were killed in 40 days of fighting in the city, including 700 civilians, among them 160 children, according to a Syrian activist group.

Syrian state TV reported yesterday that dozens of residents had left rebel-held areas in Aleppo and were taken to shelters in the Government-controlled part of the city.

Also, Aleppo’s governor, Hussein Diab, called on insurgents in the eastern neighbourhoods to turn themselves in, hand over their weapons, and take advantage of an amnesty decree issued recently by Syrian President Bashar Assad.

“We are at a new stage that requires making the decision to embrace reconciliation,” Diab said in a statement carried by the state news agency,

SANA. He urged insurgents to halt what he called the bloodshed and destruction and affirmed that all who turned themselves in and surrendered their weapons would be treated well and allowed to return to normal life.

Moscow laid the blame for yesterday’s violence squarely on the Opposition. Russian Defence Ministry spokesman Major General Igor Konashenkov said in an e-mailed statement that both “terrorists and the Opposition” are using the truce to “boost their forces and prepare for renewed hostilities”.

Konashenkov says Moscow still has not been able to contact the US-backed Opposition to coordinate ceasefire efforts despite Washington’s assurances. He said the US has not even tried to get the Opposition to hold its fire.

US Secretary of State John Kerry fired back in an interview with

CNN, saying Russia needs to stop Assad from attacking the Opposition and blocking aid delivery.

Kerry said Assad was a “spoiler” in the ceasefire, and called on Moscow to “stop the grandstanding, stop the showboating, and get the humanitarian assistance going”.

Kerry also said it was important to set up the Joint Implementation Center in order to prevent the “terrible thing that happened yesterday, that we all acknowledge and regret, but it happens when you have conflict”. He appeared to be referring to the US-led air strikes in eastern Syria.

Earlier yesterday, Islamic State militants shot down a Syrian warplane as Syrian forces regained ground lost to the extremists following Saturday’s air strikes, state media said.

Syria’s Foreign Ministry’s statement, sent to the UN Security Council, said American warplanes repeatedly attacked its army positions and that the air strikes were “on purpose and planned in advance”.

Russia’s military said it was told by the Syrian army that at least 62 Syrian soldiers were killed in the Deir el-Zour air raid and more than 100 wounded. The Russian air force has been carrying out strikes across Syria to bolster Assad’s forces for nearly a year, and the two militaries work in close coordination.

Russia said the United States was being obstructive and deceptive regarding the air strike. A Foreign Ministry statement said, the Americans “not only turned out to be unable to give an adequate explanation of what happened, but also tried, as is their custom, to turn everything upside down”.