CAIRO (AP) — Cooking gas cylinders packed into the basement of a four-story apartment building in northern Egypt exploded on Friday, collapsing the building and killing at least six people. Twenty-seven were injured, authorities said.

The explosion and the subsequent collapse took place in the Nile Delta city of Damanhour, about 150 kilometers (99 miles) north of the capital, Cairo. The office of Egypt’s public prosecutor said the cylinders were stored in violation of regulations.

Among the dead were three children, the youngest was a 3-year-old, authorities said in a separate statement.

Search efforts were ongoing to find those still missing beneath the rubble while the injured were transported to a nearby hospital, it said. No further details were immediately provided.

Building collapses are common in Egypt, where poor construction and shoddy building maintenance are common across the country, especially in shantytowns, low-income neighborhoods and rural areas.

Last month, six people were killed in an apartment block collapse in the southern city of Asyuit.

After Friday’s collapse, Egypt’s Ministry of Social Solidarity said the families of those killed would receive 50,000 Egyptian pounds, or about $1,638, in aid. Families who lost their homes in the collapse would receive 20,000 Egyptian pounds, which is around $655, it said.

The government has tried to crack down on illegal construction in recent years following decades of lax law enforcement. Also, authorities are building new cities and neighborhoods to rehouse those living in poorly constructed buildings.

However, many cities across the North Africa country still have large swaths of unlicensed apartment blocks and shantytowns in breach of building regulations.

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