MOSCOW (AP) — Four people died in Russian hospitals overnight, bringing the death toll from last weekend’s nightclub fire to 117, an emergency official said Tuesday.

About 30 of the 120 hospitalized remain in critical condition after Saturday morning’s blaze in a nightclub in Perm, sparked by an indoor fireworks display.

Prosecutors suspect negligence and on Monday charged four people — the club’s co-owner, its manager and entertainment director and the head of a fireworks company whose indoor show sparked the blaze. All are in custody in the Ural Mountains city.

Oksana Butina, a local Emergencies Ministry spokeswoman, told The Associated Press that the four new deaths all occurred in hospitals in Perm.

Most of the dead were killed by burns or gas inhalation, officials have said, although some were crushed as the crowd tried to flee through a single exit.

Video footage from Russian television showed the club’s ceiling covered in a pattern of woven twigs, which were set alight by one of the pyrotechnics. The ceiling behind the twigs reportedly was highly flammable plastic.

Enforcement of fire-safety standards is infamously poor in Russia and there have been several catastrophic blazes at drug-treatment facilities, nursing homes, apartment buildings and nightclubs in recent years.