GAZA CITY (AFP) - Five Palestinians were killed as Israeli combat helicopters struck militants in the northern Gaza Strip and the army warned that its huge military offensive in the area could last for weeks.
Since Israeli unleashed its military might six days ago, 71 Palestinians have been killed in the deadliest raid on the Gaza Strip since the start of the Palestinian uprising against Israeli occupation four years ago.
Israeli army chief Moshe Yaalon warned that the onslaught, which is aimed at preventing rocket attacks by Palestinian militants, could last for weeks.
"Our forces are ready to operate not just for days but for weeks," General Yaalon told military radio on Monday.
"In the war on terror, one does not resolve the problem in a single operation but by a series of operations and we will continue for as long as it takes."
And the death toll mounted before dawn, with four militants from the Palestinian Islamic movement Hamas killed in an Israeli air strike on the densely populated Jabaliya refugee camp.
The army said the men had been spotted as they were preparing to lay an explosive charge in the path of an Israeli patrol.
A fifth Palestinian was gunned down in the camp three hours later. His identity was not immediately known.
Despite the huge army presence in Gaza, two rockets landed on the Israeli town of Sderot just across the border on Monday, leaving one person with shrapnel injuries.
Israeli Prime Minister Ariel Sharon launched the operation, codenamed Days of Penitence, precisely to stop such attacks, which killed two Israeli children last Wednesday.
Another three Israelis, including two soldiers, have been killed in the fighting in Gaza since the offensive began on September 28 -- the fourth anniversary of Sharon's visit to the Al Aqsa mosque compound in Jerusalem which triggered the intifada.
The improvised Qassam rockets, which are generally inaccurate and for the most part land harmlessly, are named after the hardline Islamist group's armed wing -- the Ezzedin al-Qassam Brigades
Sharon, who plans to pull out the military and all Jewish settlers from the occupied Gaza Strip next year, warned Sunday that the operation would last "as long as the danger exists."
He also insisted that the evacuation would not take place "under fire" from hardline militants.
The Palestinian cabinet has declared a state of emergency in the face of the onslaught while the Arab League is planning to appeal to the United Nations for urgent action to halt Israel's "continuing war of extermination against the Palestinian people."
Also overnight, two senior Hamas commanders were seriously injured in an Israeli helicopter gunship attack in Gaza City, Palestinian hospital and security sources told AFP.
One of the men, Mohammad Al Simri, is a leading figure in Hamas's armed wing and escaped a similar targetted killing attempt by Israel earlier this year.
The death toll from the latest operation operation has swept past that of a May operation in the southern Gaza city of Rafah, where more than 40 Palestinians were killed as Israel sought to destroy cross-border weapons-smuggling tunnels.
A number of foreign governments, as well as the International Committee of the Red Cross, have expressed concern at the operation, while Israel's arch-foe Iran said the Jewish state was guilty of "genocide".
But the United States has refrained from criticising Israel, saying only that it should use "proportional force" and avoid civilian casualties.
The Israeli army has been battling with rocket attacks for months, and mounted a massive five-week offensive in northern Gaza in July.
The first fatal attack from a Qassam rocket -- which can carry a five-kilo (11-pound) explosive charge and have a 10-kilometre (six-mile) range -- occurred in June, when an Israeli toddler and a man were killed in Sderot.