Mourners attend the funeral prayers for nine members of Alemdar family killed in a collapsed apartment building, in Istanbul, Saturday, Feb. 9, 2019. Turkey's President Recep Tayyip Erdogan says there are "many lessons to learn" from the collapse of a residential building in Istanbul where at least 17 people have died.(AP Photo/Emrah Gurel)

Mourners attend the funeral prayers for nine members of Alemdar family killed in a collapsed apartment building, in Istanbul, Saturday, Feb. 9, 2019. Turkey's President Recep Tayyip Erdogan says there are "many lessons to learn" from the collapse of a residential building in Istanbul where at least 17 people have died.(AP Photo/Emrah Gurel)

ISTANBUL (AP) — Turkey’s interior minister says the death toll from a collapsed apartment building in Istanbul has risen to 21.

Minister Suleyman Soylu spoke late Saturday, saying those who made “mistakes” would be held accountable. The eight-story building in the city’s Kartal district collapsed on Wednesday.

Rescue workers remain at the site and it is unclear how many more people are missing. The collapsed building had 14 apartments, 43 registered residents and three businesses.

Thirteen people pulled from the rubble have been hospitalized and seven remain in intensive care. Chief Doctor Recep Demirhan says that two are in very serious condition, according to Turkey’s official Anadolu news agency.

Officials have said the top two floors of the building were built illegally using low quality construction materials.