Hours before a vote at the United Nations, where Russia may decide again to block international efforts for a cease-fire in Syria, CBS News spoke Friday morning with a family living in what the United Nations has described as "hell on earth." They were safe, but they hadn't slept.

Explosions continued throughout the night, and the mother told CBS News correspondent Charlie D'Agata over the phone that she and her daughters are too terrified to step outside their apartment.

The previous day, Syrian dictator Bashar Assad's ferocious bombardment of the eastern Ghouta suburbs of Damascus crept closer by the hour to the apartment where 10-year-old Noor and her sister Alaa, 8, are hiding with their mother.

Then an airstrike sent shards of glass and debris flying through their apartment, slashing Alaa's forehead. We got through to their terrified mother, Shamza Khatib, after the explosion.

"Please help us," she begged. "We are in danger. But the world is just watching what is happening in Ghouta. Why? Why? Why don't (you) help us?"

Her message when we spoke to her again on Friday morning was less panicked, but no less desperate.

"In the name of humanity, help us, we are in need," she said.

Noor Khatib, 8, touches a cut on her face moments after an airstrike by forces loyal to Syrian dictator Bashar Assad hit near her apartment in the Damascus suburbs of eastern Ghouta, Feb. 22, 2018, in a screengrab from a video posted by her family on Twitter. TWITTER

Her two little girls took to Twitter days ago to tell the world about their plight. They have appeared in videos -- speaking in English so that more people will listen, Noor says.

"Warplanes and helicopters attack our neighborhoods," Noor says in one videos. "The children of Ghouta are being mortared. Save the children of Ghouta before it's too late."

They are among 400,000 civilians believed to be trapped in eastern Ghouta amid the merciless onslaught by Russian-backed Syrian forces, who insist they are targeting Islamic extremists that fire rockets into the capital city.

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At the United Nations in New York, discussions of a humanitarian cease-fire have repeatedly been stymied by Russia. The Security Council was expected to vote on the latest cease-fire proposal later Friday, and it remained unclear whether Moscow would wield its veto power.

CBS News' Pamela Falk reports that the cease-fire proposal was introduced earlier this month by Sweden and Kuwait, but was delayed by Russia. Modifications have been made, in consultation with the Russian delegation, to try and get it passed -- all while the humanitarian situation deteriorates.

State Department spokeswoman Heather Nauert struggled on Thursday to provide answers to the violence, telling journalists, "I don't know what some of you expect us to do."