JERUSALEM, Jan 11: Israel’s military has fired artillery shells packed with the incendiary agent white phosphorus over populated areas of Gaza and a crowded refugee camp, putting civilians at risk, said Human Rights Watch on Sunday.

At least 29 Palestinians were killed on the 16th day of a devastating Israeli offensive, taking the death toll to nearly 900 people.

“Israel is getting close to achieving the goals it set for itself,” Prime Minister Ehud Olmert told his cabinet in Jerusalem.

“But patience, determination and effort are still needed to realise these goals in a manner that will change the security situation in the south,” Olmert said, referring to Israeli towns where life has been disrupted by Hamas rocket salvoes.

Thick black smoke rose over the city of Gaza as fighting raged on in the Hamas-ruled territory in defiance of international calls for a ceasefire. Medical workers said about half the Palestinians killed on Sunday were civilians.

On the usually quiet Israeli-occupied Golan Heights, shots were fired from Syria at Israeli army engineers working on the frontier fence, but no one was hurt and it was not immediately clear who was responsible, an Israeli military spokesman said.

Backed by helicopter gunships, Israeli troops and tanks pushed into eastern and southern parts of the city of Gaza, confronting Hamas militants who fired anti-armour missiles and mortar bombs.

At the edge of the city, Mahmoud Abu Hasseera surveyed the rubble of his house, in an area where Israeli tanks and infantry had battled Palestinian fighters hours earlier.

“Where should we and our children go to sleep? To the streets?” he asked. “We have no mattresses, blankets, cooking gas, food or water. Everything was destroyed.”

Hamas leader Khaled Meshaal said his ruling Islamist group would not consider a ceasefire until Israel ended its air, sea and ground assault and lifted its blockade of Gaza. A Hamas delegation held talks in Cairo on an Egyptian truce plan.

Researchers from the rights group said they witnessed hours of artillery bombardments on Friday and Saturday afternoon from Israel’s border in which shells burst over the Jebaliya refugee camp in northern Gaza, sending out trails of burning smoke that indicated the shells contained white phosphorus.

The substance can cause serious burns if it touches the skin and can spark fires on the ground, the rights group said in a written announcement calling on Israel not to use it in crowded areas of Gaza.

Military spokeswoman Maj Avital Leibovich refused to comment directly on whether Israel was using phosphorus, but said the army was “using its munitions in accordance with international law.”

Human Rights Watch said it had no way to investigate whether anyone was injured on the ground because its researchers have been barred by Israel from entering the territory.

Associated Press reporters in southern Gaza on Sunday saw several patients at Nasser Hospital in the town of Khan Younis with serious burns that the chief doctor said might have been caused by phosphorus. He said, however, that he did not have the resources or expertise to say with certainty what caused the injuries.

One of the patients, a young man, had severe burns that left skin on his face and body peeling off in places.

White phosphorus is not considered a chemical weapon, and militaries are permitted under laws of warfare to use it in artillery shells, bombs and rockets to create smoke screens to hide troop movements as well as bright bursts in the air to illuminate battlefields at night.

Israel is not party to a convention regulating its use. Under customary laws of war, however, Israel would be expected to take all feasible precautions to minimise the impact of white phosphorus on civilians, Human Rights Watch said.

“What we’re saying is the use of white phosphorus in densely populated areas like a refugee camp is showing that the Israelis are not taking all feasible precautions,” said Marc Garlasco, a senior military analyst for the rights group.

“It’s just an unnecessary risk to the civilian population, not only in the potential for wounds but also for burning homes and infrastructure.”

Garlasco was among researchers on a ridge about 1.5 kilometres from the Gaza border who observed the shelling from a 155mm artillery unit.

Some of the burning trails of smoke caused fires on the ground that appeared to go out after a few minutes, said Garlasco, who formerly worked at the Pentagon where he was in charge of recommending high-value targets for air strikes during the 2003 invasion of Iraq.

Each 155mm shell contains 116 of what Garlasco described as wafers doused in phosphorus that can be spread over an area as large as a sports field, depending on the height at which it detonates. The phosphorus ignites when it comes in contact with oxygen.Human Rights Watch has not been able to confirm whether there have been any civilian casualties from phosphorus. The group has a consultant working for it inside Gaza but he has been unable to move around due to the danger. Foreign journalists have also been barred from entering Gaza.

An AP photographer and a TV crew based in Gaza visited Nasser Hospital in Khan Younis on Sunday and recorded images of several burn patients.

One of them, Haitham Tahseen, recalled sitting outside his home with his family in the morning when something exploded above them.

“Suddenly, I saw bombs coming with white smoke,” said the man, whose burned face was covered with medical cream. “It looked very red and it had white smoke. That’s the first time I’ve seen such a thing.”

His cousin, in another hospital bed, was more severely burned, with patches of skin peeling off his face and body, and had to be wrapped with thick white bandages.

The hospital’s chief doctor, Youssef Abu Rish, said the burns were not from contact with fire, but he couldn’t say what sort of substance caused them. He said information he collected on the Internet indicated it could have been white phosphorus.—Agencies