A mob of lawyers smashed windowpanes and equipment at a Lahore hospital and also set several vehicles on fire.

More than 100 lawyers have stormed and ransacked a hospital in Pakistan to avenge what they said was an assault by doctors there on a fellow advocate, and an elderly patient died during the disturbance, authorities said.

Zulfikar Hameed, Lahore city police chief, said the mob smashed windowpanes, doors and equipment at the cardiology hospital and also set several vehicles on fire on Wednesday.

Some of the protesters fired gunshots and pelted arriving police with stones and bricks, according to a hospital doctor, Ashraf Nizami. Several lawyers were arrested, police said.

“It was catastrophic for hours,” Nizami said, adding that a 70-year-old female patient had died and several patients were left unattended for hours, during the violence.

Nizami said the attackers forced doctors and nurses to flee, leaving patients in emergency and intensive care unattended.

Police fired tear gas to quell the mob while terrified patients and hospital staff fled to safety, officials said.

Lahore government official Kamran Ali said the lawyers were enraged over what they said was the beating of a lawyer by doctors at the hospital over his refusal to get in a queue of patients.

He said the lawyers were particularly angry about the doctors disseminating a video on social media showing the beating.

The mob also attacked provincial information minister Fayaz-ul-Hasan Chauhan when he got to the scene and tried to negotiate with the lawyers.

Prime Minister Imran Khan’s office launched an investigation into the incident. “It is a shame that some people would go and attack a hospital,” his spokesman Nadeem Afzal Chan said.