Israel should not use artillery fire to target rocket-launching militants in the Gaza Strip if the fire is aimed at populated areas, the defense establishment's legal adviser recently told Defense Minister Ehud Barak.

"Artillery fire is permissible only in relatively open areas," Ahaz Benari wrote in the legal opinion. "Artillery fire at urban areas is problematic, if the assessment is that the chance that the shell will hit the launchers is relatively low, while the risk that many civilians will be hurt is substantial."

Barak and Chief of Staff Gabi Ashkenazi have previously expressed doubts about an extensive Israel Defense Forces operation in Gaza now. Benari's opinion appears to be backed by leading military prosecution officials, though Attorney General Menachem Mazuz has yet to express a firm opinion on the matter. Prime Minister Ehud Olmert has promised to hold a cabinet meeting on the issue shortly.

Benari wrote the legal opinion December 7, after cabinet ministers called for a reexamination of the steps Israel is using to counter Qassam fire. The opinion reviews international law on the matter and finds that while there is no wholesale ban on artillery fire at sites from which rockets were launched, the fire should be aimed at military targets and be able to distinguish between the target and civilians or civilian property.

The opinion also states that if damage to civilians or their property is expected as a result of the artillery fire, the IDF must make sure the damage is not much greater than the expected military benefit - an expression of the legal principle known as proportionality.

Meanwhile, Palestinian militants in Gaza fired seven Qassam rockets and mortar shells on southern Israel yesterday, causing no injuries. Defense officials said last night that even though Hamas leaders are saying the cease-fire with Israel will not be extended past Friday, the organization has not completely given up on continuing the lull.

The IDF developed a detailed procedure for artillery fire in Gaza in 2006, which approves shooting only in open areas and mandates that a distance be kept from buildings. But the IDF halted its use of artillery fire altogether after accidentally killing 18 Palestinian civilians in the Gaza town of Beit Hanun in November 2006, even though the artillery fire was meant to target open areas.

The legal opinion also addressed the creation of ghost towns in Gaza, involving the eviction of Gazans from their homes in areas Palestinian militants use for launching rockets, as an Israeli response to the rocket fire. Benari said international law allows Israel to warn the residents of the intended IDF artillery response and evacuate a particular area for a short time. But even then, he said, the IDF cannot engage in carpet bombing, which would lead to the intended massive destruction of property that does not constitute a legitimate target. He said Israel must also take into account that some civilians will remain in the area even if they are advised to leave.