Pressure grew on Israel to end the use of controversial white phosphorus yesterday as The Times saw more evidence of its deployment around civilian populations in Gaza.

More than 50 people with burns were taken into Nasser Hospital in the southern town of Khan Yunis, in what the hospital director, Youssef Abu Al-Reesh, said was a massive case of exposure to white phosphorus.

“We don’t have the medical experience to judge these cases, but we searched the internet according to the cases we have, and it indeed confirmed that it’s white phosphorus munitions. I have been working in this hospital for ten years and I have never seen anything like this.”

The 1980 Geneva treaty says that white phosphorus should not be used as a weapon of war in civilian areas, but there is no blanket ban on its use as a smokescreen or for illumination. It produces a thick white smoke when exposed to oxygen, but can cause severe burns and melt flesh to the bone if it comes into contact with skin.

The sudden influx of burns patients at Nasser Hospital coincided with Israel’s expanded ground offensive, which included the Al-Qarara and Kuza’a suburbs of Khan Yunis.

Muhammad Tahseen, 20, said that he was sitting outside his home in Al-Qarara when a shell exploded above. He described watching his two cousins writhe in pain as he stood metres away, unable to help. “There was an explosion and white smoke. I saw my cousins screaming . . . I saw them burning and their clothes burning. I saw their skin melting.”

Doctors said that they were unable to provide further help to Muhammad Nabih Ahmed, 17, listed in critical condition with burns to the chest and back. The family hope to get Ahmed treated in an Egyptian hospital. But travel from Khan Yunis to the southern border with Egypt is treacherous, and many aid organisations have ceased travelling along the roads.

When first questioned by The Times last week an Israeli military spokesman “categorically denied” using white phosphorus in Gaza. In a statement issued yesterday the spokesman’s office said: “We don’t specify operational details, nor the type of ammunition that we use, but any ammunition that is used by the IDF [Israel Defence Forces] is within the scope of international law.”

Human Rights Watch said it was sure Israel had used white phosphorus. “The use of white phosphorus in densely populated areas of Gaza violates the requirement under international humanitarian law to take all feasible precautions to avoid civilian injury and loss of life,” it said.

Further research by The Times into the type of US-made shells being fired by Israeli gunners on the border with Gaza uncovered additional evidence that the light blue munitions, known as M825A1s, are carriers of white phosphorus, impregnated in more than 100 felt wedges.

The lot number – PB-91J011-002A – visible in a photograph published by The Times last week indicates that the shells being used by the IDF were assembled in September 1991 at Pine Bluff arsenal in America, where all US white phosphorus munitions are reportedly made. The contractors are Chamberlain Manufacturing [metal parts only], General Dynamics, and Ordnance and Tactical Systems.

White phosphorus can be air-burst or ground-burst. It emits a distinct garlic smell. When air-burst, it covers a larger area than ground-burst and is useful to mask large troop movements. However, this spreads the incendiary effect over a wider area.

Munir Albarsh, the Head of Emergency Medicine at Gaza’s Ministry of Health, said that doctors were collecting tissue samples at hospitals across Gaza to send for phosphorus testing at international laboratories. He added that the ministry would demand an independent international investigation into Israel’s use of white phosphorus.

Times Recommends

• Henning Mankell: ‘If Wallander was alive, I wouldn’t be a friend of his’
• Secret society's skull and crossbones for sale
• Nigerian leader vanishes after medical treatment