BEIRUT -- A series of artillery rounds lobbed Wednesday on Syria's eastern Aleppo district killed 26 civilians, including seven children, as they fled a government ground offensive in the besieged enclave.

It was the second time the Jub al-Quba neighborhood, in the historic district of the rebel-held eastern side of the city, was struck in as many days.

An airstrike Tuesday, which activists blamed on the government, killed 25 civilians in the same area. They also were believed to have been newly displaced from the government onslaught on the northern parts of eastern Aleppo.

Meanwhile, eight civilians, including two children, were killed in shelling on the government-held western side of the city, according to state media.

The government blamed rebels for the attack.

The embattled opposition fighters clashed heavily on the southern edge of the enclave with government-allied troops, who made new gains in the government offensive that has cleaved the rebel-held part of the city.

The Syrian government pushed its way into the 17-square-mile rebel-held enclave over the weekend, making its first territorial gain in the area seized by the opposition fighters since 2012.

Government officials said they want to "liberate" the area, calling the opposition fighters "terrorists" and accusing them of holding civilians there hostage.

A number of passageways opened to allow civilians to leave before the offensive, but none of the residents took advantage of it, citing fears of being arrested or forcibly conscripted.

The passageways were not U.N.-supervised.

In New York on Wednesday, Syria's U.N. Ambassador Bashar Ja'afari accused the rebels of opening fire on the civilians as they tried to flee eastern Aleppo.

The bodies of the victims of the Jub al-Quba attack Wednesday lined the streets, as their bags and few belongings lay close by their sides, photographs showed.

Jawad al-Rifai, who took the pictures for the Aleppo Media Center, said they were civilians -- mostly women and children -- fleeing shelling and air strikes on other parts of the city.

"They were fleeing on foot. They were coming to our side," said Ibrahim Al-Haj, a member of the Syrian Civil Defense teams, explaining the displaced were heading to what they thought was safer ground. "There were children, baby bottles and bags all over."