Three hospitals in southern Lebanon have been attacked by Israel in under a week, wounding more than 150 people and killing nine, according to Lebanon’s ministry of health.

Israel carried out an attack in the immediate vicinity of the public hospital in Tebnine on Wednesday, just days after strikes next to the Hiram and Jabal Amel hospitals in Tyre. The attack next to Jabal Amel on Monday killed four people and injured 127 – most of whom were medical staff.

“It was an ordinary day at the hospital and then suddenly for no reason, they targeted the hospital. It was a catastrophe,” said Wael Mroueh, the director of Jabal Amel. The strike hit the building directly in front of the hospital, levelling it.

The force of the blast knocked out the hospital’s electricity, destroyed much of the first floor and forced medical staff to evacuate patients who were hooked up to machines in the intensive care unit, which was also damaged.

Mroueh said: “I never expected something like this to happen. We prepared ourselves psychologically that maybe some of our medical staff could be targeted, but a huge strike like this, in this way. We didn’t expect it.”

The World Health Organization said the attacks deprived the most vulnerable patients of medical care. Access to essential services was already “critically constrained”, said the UN agency’s representative in Lebanon, Abdinasir Abubakar, who called for the attacks to stop

The hospitals are among the few remaining functional healthcare facilities in south Lebanon, an area which has been subject to mass displacement. The third hospital in Tyre had escaped damage but was overwhelmed and dealing with an influx of injured patients, according to Abubakar.

Tyre, one of the largest cities in south Lebanon, is hosting displaced people from surrounding villages, many of whom have limited access to medical care.

At least 130 medical workers have been killed by Israel and 162 ambulances and healthcare facilities have been struck since the fighting between Hezbollah and Israel started on 2 March, according to the Lebanese ministry of health. It said two emergency responders were killed and a third critically wounded by an Israeli strike on an ambulance on Wednesday.

The Israeli military said it had struck “Hezbollah infrastructure in the area of Tyre” and acknowledged the hospital was “affected incidentally” but was not a target of the strike. It accused Hezbollah of “taking over” one of the hospitals it struck, in Tebnine, and said medics had treated wounded fighters.

The Lebanese ministry of health called the accusation a “fabrication” and said: “This threat is yet another episode in the escalating series of Israeli attacks on health institutions.”

The International Committee of the Red Cross, the Lebanese Red Cross and the Lebanese army all have a medical presence in Tebnine’s hospital.

Analysts and human rights experts have said the attacks on healthcare facilities were aimed at degrading the conditions for life in south Lebanon. Targeting medical facilities and healthcare workers is a war crime.

Despite the damage to Jabal Amel, Mroueh said the hospital was again receiving patients. “On the day the strike happened, we performed two childbirth deliveries. We’re continuing to receive victims of airstrikes,” he said. “None of the doctors or nurses left. They said they wanted to continue working.”

The fighting started on 2 March when Hezbollah launched rockets at Israel in retaliation for the killing of Iran’s supreme leader, Ayatollah Khamenei. A ceasefire between Lebanon and Israel was signed on 17 April but fighting has not stopped outside Beirut.

More than 3,468 people have been killed by Israeli strikes in Lebanon since 2 March, while at least 21 Israeli soldiers have been killed by Hezbollah along with two civilians inside Israel.