At least 17 people were killed and eight injured on Wednesday when a 12-storey building collapsed in the Egyptian coastal city of Alexandria, a security official told AFP.
More people were trapped under the rubble and were calling out to rescue teams for help, the official added.
Emergency services rescued 10 people after the building housing 24 families in the Maamura district of Alexandria collapsed in the early hours, a security official said earlier.
Another two people were killed when a three-storey building collapsed in the Nile Delta province of Daqahliya, a security official told AFP.
"A mother and her child were killed and eight others injured when the building collapsed," the official said, adding that an estimated 10 people were still under the rubble.
Egypt has seen a number of construction disasters over the years, many of them blamed on planning violations or bad maintenance.
The latest incidents will pile pressure on President Mohamed Morsi's government which has been criticised for failing to address Egypt's chronic problems.
On Tuesday, 19 people died and over 100 injured when a train carrying military conscripts derailed southwest of Cairo.
According to media reports, it is the fifth deadly train accident since Morsi was sworn in as Egypt's first Islamist president in June.
The railway network's poor safety record stems largely from lack of maintenance and decades of poor management. In Egypt's deadliest railway tragedy, the bodies of more than 360 passengers were recovered from a train after a fire in 2002.
Egyptians have long complained that the government has failed to deal with the country's transport problems, with roads as poorly maintained as railway lines.