By Nidal al-Mughrabi
GAZA (Reuters) - Israel killed five Palestinian militants in a third straight day of air raids across the Gaza Strip while militants fired dozens of rockets and mortars at Israel, defying the efforts of mediators to stem the violence.
The death toll since Israel launched its retaliation for an attack on a school bus that critically wounded a teen-ager on Thursday climbed to 19 Palestinian militants and civilians.
With Egypt and the United Nations reportedly trying to achieve a ceasefire, militants fired a new volley of rockets at southern Israel, causing no casualties but spreading panic.
Israeli cabinet minister Gideon Sa'ar said Israel would keep responding to the attacks from Gaza, where it maintains tight controls over the entry and exit of people and goods. Israel said some 40 rockets had been fired from Gaza Saturday.
"We will not permit sporadic shootings or the disruption of life inside Israel," Sa'ar told Israel Radio. "We will continue ... to implement a principle of defending our citizens."
Before dawn, Israeli forces killed a local Hamas commander in the southern Gaza town of Rafah, bordering Egypt, as well as two bodyguards, in an air strike on his vehicle, medics said.
Israel blamed the commander for a rocket strike on the city of Eilat launched from the Sinai Peninsula some months ago.
Another air strike at daybreak killed a further militant.
As dusk fell, Israeli air strikes on two targets near Gaza City killed one militant and wounded three others, Palestinian medics said.
Abu Ubaida, a masked spokesman for the armed wing of the Hamas Islamist movement that controls Gaza, defiantly told a news conference that his group had launched at least 60 mortars and rockets since Friday, and would reject any ceasefire.
"There is no room to talk about calm between us," Ubaida said. "The blood of our people is very dear and cannot be in vain."
ARAB LEAGUE MEETING
Hamas had threatened earlier to widen the range of its rocket fire unless Israel stopped its bombing raids, and demanded an Arab League meeting on the fighting, which Palestinian officials said would convene in Cairo Sunday.
Israeli Prime Minister Benjamin Netanyahu met senior officials after the Jewish sabbath Saturday evening.
But there were signs of efforts to stop the bloodshed.
Israel Radio said the U.N. Middle East envoy, Robert Serry, was trying to mediate a halt to the violence, and the Egyptian state news agency said Egypt was engaged in similar efforts.
Hamas spokesman Sami Abu Zuhri tried to step back from an earlier claim of responsibility for Thursday's attack on the Israeli bus.
"It was not known that the bus targeted on the outskirts of Gaza carried schoolchildren," he told Reuters.
He said the road near the frontier was inside an "Israeli military zone" commonly used for attacks on Gaza.
Two years of periodic, low-level skirmishing on the border escalated suddenly last month when Hamas showered rockets on Israel. Hamas had largely withheld fire since a Gaza war in late 2008 in which 1,400 Palestinians and 13 Israelis were killed.
Thirty-seven Palestinians have now died in the latest round of bloodletting.
Political analysts have explained the conflagration as an effort by Hamas to divert attention from demands, fueled by pro-democracy unrest in the Arab world, for an end to its split with the Western-backed Fatah movement in the West Bank.
(Writing by Allyn Fisher-Ilan; Editing by Kevin Liffey)