Israel on Saturday ruled out an immediate truce in Gaza, saying the onus was on Palestinian militants to stop launching rockets from an arsenal it suggested could be depleted within days, while its aircraft kept up strikes in the enclave.
"We're not holding cease-fire talks," National Security Adviser Tzachi Hanegbi told a municipal event near Jerusalem, adding that Israel's top priority was presently firing on militants.
Two Palestinians were killed in an Israeli raid on the outskirts of Nablus in the northern West Bank, where clashes had erupted, the Palestinian Health Ministry said. A military spokesman said gunmen exchanged fire with Israeli forces.
Islamic Jihad's armed wing said it would press on with rocket salvos as fighting entered a fifth day. "The resistance prepared itself for months of confrontation," Islamic Jihad said a statement.
The Israeli military said aircraft struck Islamic Jihad command centers and rocket launchers in Gaza. Huge clouds of smoke rose as loud explosions ripped through areas bombed.
In the Deir Al-Balah area of the central Gaza Strip, a building was flattened as houses nearby were knocked down. There were no reports of casualties as residents sifted through piles of rubble.
"Destruction is miserable, the mind doesn't accept it," a resident, Marwan Al-Dirawi, told Reuters.
Airstrikes on a house also damaged the nearby Shuhada Al-Aqsa hospital, wounding a number of nurses and patients with flying shrapnel, Eyad Abu Zaher, the hospital's director, said.
Israel's military says it has made every effort to limit civilian casualties and damage to houses and accuses Islamic Jihad of deliberately locating its command centers in residential areas.
From dawn, Gaza militants fired rockets, setting off sirens and sending Israelis across the border running to bomb shelters. At least two people were badly wounded by shrapnel, Israel's ambulance service said.
Egypt has been trying to mediate a truce to the latest outbreak of violence, which has so far killed at least 33 Palestinians and one Israeli.
At least four women and six children have died in Gaza, an impoverished coastal territory blockaded by Israel and Egypt since 2007. In Israel, one woman was killed when an apartment was hit by a Gaza rocket near Tel Aviv.
A Palestinian official familiar with the truce talks described them as "complicated" and "tough" but also said that Cairo was pressing ahead with its efforts.
Six top commanders of the Iranian-backed Islamic Jihad have been killed since Tuesday, when Israeli forces launched a campaign against the group, which it said was planning attacks.
Israeli military officials have said they have seen no sign that Hamas, the Islamist group that controls the Gaza Strip, has fired missiles itself and air strikes have so far targeted only Islamic Jihad sites.
Islamic Jihad, the largest armed group in Gaza after Hamas, has since fired more than 1,000 rockets, some deep into Israel.
Hanegbi said its arsenal had stood at 6,000 rockets.
Islamic Jihad has not provided details on its weaponry, but 5,000 remaining projectiles would enable it to keep up an intense rate of fire for several days. That timeline would likely change were Hamas to join the fighting.
Like Hamas, Islamic Jihad spurns coexistence with Israel and preaches its destruction. Top ministers of Israel's religious nationalist government rule out any state sought by Palestinians in territories captured by Israel in the 1967 Middle East war.