Aleppo, SYRIA - A building collapsed Sunday in Syria's second city of Aleppo, killing 13 people including children, authorities and media reported.

The state news agency SANA had initially given a death toll of 10 before quoting an interior ministry statement revising it upwards to 13 and projecting that it was likely to rise.

A Kurdish news agency meanwhile said five children were among the dead, and a war monitor said they were all Syrians displaced during more than a decade of fighting in the country.

Only one person had been rescued from the rubble, the interior ministry said, adding that rescue and search efforts were ongoing.

The five-story building, which was inhabited by seven families, had collapsed in the early hours of the day, the ministry added.

Locals told AFP that about 35 people lived in the building.

Video footage shared on state television showed dozens of rescue workers toiling to unearth people from the rubble while bulldozers worked to clear the debris.

SANA quoted a police source as saying earlier that the building, located in Aleppo's Sheikh Maksoud neighborhood, had collapsed 'due to a water leak' in the foundations.

Much of Aleppo was destroyed during Syria's nearly 12-year conflict, with many of the remaining buildings left in a decrepit state.

The Britain-based Syrian Observatory for Human Rights reported that the victims were all displaced people from the northern district of Afrin.

The Sheikh Maksoud neighborhood is predominantly inhabited by Syrian Kurds and governed by the People's Protection Units (YPG).

Many of its residents fled from Afrin after Turkey began an offensive there in 2018.

Nearly half a million people have been killed in Syria's conflict since it broke out in 2011, and about half of its pre-war population has been displaced.

Many of those displaced have had to move into buildings that are structurally unsound, resulting in relatively frequent collapses.

Last September, a building collapse in the Ferdaws neighborhood of Aleppo killed 10 people, including three children.

And in February 2019, another collapse in the city killed 11 people, including four children.