Bana Alabed's mother, Fatemah, said on Twitter Wednesday that the eastern Aleppo neighborhood where they live had been captured by the Syrian regime.
"Our house and area fall to the army," said the tweet, which was signed by Fatemah. "We are trapped under bombs that didn't stop since last night."
Syrian government troops now control most of the neighborhoods in the old city of Aleppo after days of fierce fighting against rebel forces.
Overall, the rebels now hold only about a quarter of war-ravaged eastern Aleppo, residents and activists inside the city told CNN.
One activist described the situation as "apocalyptic,"
saying the few hospitals still operating were packed with injured civilians and resembled "slaughterhouses," with no medical supplies or proper facilities.
Fears after Twitter account falls silent
Bana's account was briefly deleted Sunday
. She then came back online Monday with an alarming tweet that said, "Under attack. Nowhere to go, every minute feels like death. Pray for us. Goodbye."
Her many followers grew concerned and posted well wishes on Twitter.
But on Tuesday Bana sounded more cheerful.
"Hello my friends, how are you? I am fine. I am getting better without medicine with too much bombing. I miss you. - Bana #Aleppo," she said.
Bana's shocking message to the world
Bana's mother created the Twitter account for her daughter in late September to "share our life here to the world'' as the Syrian army launched a major offensive to recapture Aleppo.
The two have been stuck in the rebel-controlled sections of the eastern part of the city, under fierce assault by the Syrian regime and Russian warplanes.
Their mournful and shocking messages -- with videos capturing the sounds of bombing and Bana on camera pleading for help -- grabbed the world's attention.
In one image, a destroyed building is accompanied by the heartbreaking message: "This is my reading place where I wanted to start reading Harry Potter."
Another photo of rubble and twisted metal says: "This is our house, my beloved dolls died in the bombing of our house. I am very sad but happy to be alive."