Updated

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 blamed by activists on the government killed 25 civilians in the same area. They were also believed to be 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 say they want to "liberate" the area, calling the opposition fighters "terrorists", and accusing them of holding civilians there hostage.

Despite opening a number of passageways to allow civilians to leave before the offensive, 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 lied close by their sides, photos 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 that the displaced were heading to what they thought was safer ground. "There were children, baby bottles and bags all over."

The neighborhood and others around it in Aleppo's centrally-located old city have absorbed thousands of residents displaced by the advance of government troops in the east.

Abdulkafi Alhamdo, a teacher living in the Zabadieh neighborhood in eastern Aleppo, said refugees were filling up his building, most of its flats abandoned because of the war. They had close to nothing, he said, and have asked for the simplest things, including salt.

"They knock on my door all the time. They ask for a plate, or some sheets," Alhamdo said.

The Britain-based Syrian Observatory for Human Rights, which monitors the war in Syria through a network of local contacts, said tens more were wounded in Jub al-Quba.

Observatory chief Rami Abdurrahman said he predicts death tolls will rise in east Aleppo as the internal displacement creates more residential density.

The SCD in eastern Aleppo, also known as the White Helmets, put the toll at 45 killed. It blamed the government for the strikes.

Rescue efforts by the group were hampered by the lack of functioning machinery, said Rifai.

"Most of their equipment is out of service because of the targeting against their quarters," he added.

Tens of thousands of people have been displaced in Aleppo as pro-government Syrian forces press on with their campaign to reclaim the divided city.

The Observatory said more than 50,000 out of an estimated quarter-million inhabitants have been displaced by attacks on rebel-held eastern Aleppo over the past 4 days. Many of them fled to safer ground in areas under government or Kurdish control. The International Committee of the Red Cross says around 20,000 people have fled.

The Lebanese Al-Manar TV channel, operated by Hezbollah which has groups fighting on the government side in Syria, reported from the Aleppo countryside that pro-government forces were advancing in the southern portion of the city's rebel enclave.

Syrian state media announced midday Wednesday that its forces had retaken the southern Sheikh Saeed neighborhood, while the Observatory said rebels still held onto a third of the area. The Observatory added that Iraqi militia fighters were playing a central role in the government's advance from the south.

Yasser al-Youssef, a spokesman for rebel group Nour el-Din el-Zinki, said the pro-government fighters were repelled and the opposition had captured at least one of their soldiers. The group posted a video of the captured fighter.

"There is regime deployment on the southern edge of the city. They are likely to attempt an assault on the southern front," al-Youssef said.

Residents said meanwhile that after the killing in Jub al-Qubba, there was a respite in government bombing, most likely due to heavy rain.

"The rain stopped the bombing," al-Haj said.