At the American University of Beirut Medical Center, one of the capital's main hospitals, his paediatric intensive care unit has been receiving critical cases from across the country and desperate parents praying for their children's survival.

This week, Israeli strikes hit densely populated central Beirut areas not far from the hospital, with three badly wounded children pulled from the rubble.

Among them was an 11-year-old girl who had "metal shrapnel in her abdomen, and partial amputation of the foot", said Abu-Sittah, a plastic surgeon specialising in conflict injuries.

"She's now in a stable condition," added the doctor, who lives near the hospital and rushes there for emergencies.

Israeli strikes have pummelled Lebanon since Hezbollah fired rockets into Israel on March 2 to avenge the killing of Iran's supreme leader Ayatollah Ali Khamenei in Israeli-US attacks.

Lebanese authorities say that 118 children have been killed and 370 others wounded.

Abu-Sittah said he had seen "partial limb amputations, brain injuries, shrapnel in the face, shrapnel in the eye, penetrating abdominal shrapnel, a lot of fractures, a lot of broken bones, a lot of soft tissue damage... and all of this in one child."

Such wounds mean "lots of surgeries", he added, dark rings under his eyes.

- War an 'endemic disease' -

He recalled three sisters who were brought to the hospital around a fortnight ago.

"Their injuries are so bad, I have to take them to the operating room every 48 hours... to get rid of more of the dead tissue and clean the wounds so that at some stage, they're ready for the reconstructive surgery," he said.

Born in Kuwait to a Palestinian refugee father from Gaza and a Lebanese mother, Abu-Sittah has dedicated his life to treating wounded civilians in the region.

War is the "endemic disease" of the Middle East, said Abu-Sittah.

But "you never get used to" children suffering, he said.

"A child should never become faceless, they never become numbers."

His first experience of conflict was as a medical student in 1991 after the withdrawal of Iraqi troops from Kuwait during the first Gulf War, and treating the wounded would soon become his mission.

He graduated in the United Kingdom and over the decades has worked repeatedly in Gaza and Lebanon, as well as in Iraq and Yemen.

After Palestinian militant group Hamas's October 7, 2023 attack on Israel sparked war in Gaza, Abu-Sittah spent more than a month in the Palestinian territory.

Lebanon this time is "a kind of small version of Gaza", Abu-Sittah said.

While the death toll in Lebanon is far lower, health facilities and workers in the country have paid a heavy price, with the health ministry saying 40 health workers have been killed and 119 wounded.

- Ongoing care -

Abu-Sittah said four hospitals in Beirut's southern suburbs had been forced to evacuate, "one of which has a big intensive care unit for children", amid persistent Israeli bombardment of the area.

He said some badly wounded children have died because they were not transferred in time from parts of the country where health facilities are less equipped than those in Beirut.

"The Israelis are targeting the ambulances, and so moving kids from one hospital in Nabatiyeh or in the Bekaa is very dangerous," he said, referring to a city in south Lebanon and to east Lebanon's Bekaa valley area.

"It can only happen during the day, and it takes a long time," he added.

The Israeli military has accused Hezbollah of using ambulances "for military purposes", an accusation Lebanon's health ministry has described as "a justification" for crimes "against humanity".

In 2024, the doctor created the Ghassan Abu-Sittah Children's Fund, which aims to provide medical care in Gaza and Lebanon and ongoing support to wounded children after they leave hospital.

Abu-Sittah said his youngest patient in Lebanon now was a four-year-old boy whose parents and three siblings were killed, and who will need major long-term physical and psychological support after suffering a head wound and an amputated foot.

"Who's going to look after them when they go home?" Abu-Sittah said.

Many wounded children "come from poor backgrounds who don't have the means to manage all of this", he added.

"It's not just the body that's destroyed, it's the family unit that's destroyed."