Israel's top court has rejected a demand by civil liberties groups for a ban on the military's "targeted killings" of Palestinian armed faction leaders.
The High Court of Justice, rejecting petitions filed by a pro-Palestinian lobby and another rights group in 2002, ruled the tactic could be justified under laws of war.
Using air strikes or commandos, Israel has tracked and killed many Palestinian militants during six years of fighting.
Palestinian rights groups say almost 400 militants and over 200 civilians have been killed by Israeli forces in the missions.
Israeli High Court ruling
The practice has drawn global censure and charges that Israel is pursuing an illegal assassinations policy.
While Israel has largely put the controversial operations on hold as part of a Gaza Strip truce declared last month, defence officials say they are still the best last resort for preventing attacks by militants who cannot be easily caught and prosecuted.
The court ruled that the state's arguments could have legal merit in some cases.
"Arrest, investigation, and trial are not means that can always be used. At times, no such possibility exists; at times it involves such a great risk to the lives of (Israeli) troops, that it is not required," the three-justice panel said.
"Thus it is decided that it cannot be determined in advance that every targeted killing is prohibited according to customary international law, just as it cannot be determined in advance that every targeted killing is permissible according to customary international law."
In its ruling, the High Court laid out parameters for what it deemed acceptable "collateral damage" in such circumstances. "Attacks should be carried out only if the expected harm to innocent civilians is not disproportional to the military advantage to be achieved by the attack," it said.
"For example, shooting at a terrorist sniper shooting at soldiers or civilians from his porch is permitted, even if an innocent passer-by might be harmed . . . however, that is not the case if the building is bombed from the air and scores of its residents and passers-by are harmed.
"Between these two extremes are the hard cases. Thus, a meticulous examination of every case is required."
"Assassination is a form of crime that cannot be justified," said Saeb Erekat, an adviser to Palestinian President Mahmoud Abbas. "It is unbecoming of a nation state."