GAZA/JERUSALEM, May 16 (Reuters) - Israeli air strikes on Sunday killed 33 Palestinians, including eight children, Gaza health officials said, as militants fired an early morning barrage of rockets into Israel.
With no sign of an end to the worst outbreak of Israeli-Palestinian violence in years the United Nations Security Council was due to meet later on Sunday to discuss the hostilities.
The death toll in Gaza overnight jumped to 181, including 47 children, amid an intensive Israeli air and artillery barrage since the fighting erupted last Monday. Ten people have been killed in Israel, including two children.
The pre-dawn attacks were on houses in the center of Gaza City, Palestinian health officials said. A spokesman for the Israeli military said he would look into these reports.
Palestinians working to clear rubble from a building wrecked in the air strikes recovered the bodies of a woman and man.
"These are moments of horror that no one can describe. Like an earthquake hit the area," said Mahmoud Hmaid, a father of seven who was helping with the rescue efforts.
Across the border in the Israeli city of Ashkelon, Zvi Daphna, a physician, whose neighborhood has been struck by several rockets, described a feeling of "fear and horror."
The Israeli military said that Hamas, the Islamist group that runs Gaza, and other armed groups have fired more than 2,800 rockets from the enclave in six days.
This was more than half the number fired during 51 days in a 2014 war between Hamas and Israel, the military said, and more intensive even than Hezbollah's bombardment from Lebanon during the 2006 war between Israel and the Iran-backed Shi'ite group.
Many of the rockets have been intercepted by an Israeli anti-missile system while some have fallen short of the border.
Israel's security cabinet met on Sunday to discuss the next steps, amid diplomatic efforts to restore calm.
Prime Minister Benjamin Netanyahu said late on Saturday that Israel was "still in the midst of this operation, it is still not over and this operation will continue as long as necessary."
Hamas began its rocket assault on Monday after weeks of tensions over a court case to evict several Palestinian families in East Jerusalem, and in retaliation for Israeli police clashes with Palestinians near the city's Al-Aqsa Mosque, Islam's third holiest site, during the Muslim holy month of Ramadan.
There has been a flurry of U.S. diplomacy in recent days to try to quell the violence, but with little sign of success.
U.N. Secretary-General Antonio Guterres reminded all sides on Saturday that "that any indiscriminate targeting of civilian and media structures violates international law and must be avoided at all costs,” U.N. spokesman Stephane Dujarric said in a statement.
President Joe Biden's envoy, Hady Amr, arrived in Israel on Friday for talks. Biden spoke with both Netanyahu and Palestinian President Mahmoud Abbas late on Saturday, the White House said.
Any mediation is complicated by the fact that the United States and most Western powers do not talk to Hamas, which they regard as a terrorist organization.
And although the militants' rocket campaign is directed against Israel, it has also had the dual effect of marginalizing the Western-backed President Abbas - who has been powerless to stop it.
In the absence of a diplomatic breakthrough, Egypt opened the Rafah border crossing in southern Gaza on Sunday, a day earlier than planned after the Eid al-Fitr Muslim holiday, to ease passage for people needing medical treatment and other humanitarian cases, two sources at the border told Reuters on Sunday.
Both Israel and Hamas said they would continue their cross-border fire after Israel destroyed a 12-story building in Gaza City on Saturday that housed the U.S. Associated Press and Qatar-based Al Jazeera media operations.
The Israel military said the al-Jala building was a legitimate military target, containing Hamas military offices, and that it had given advance warnings to civilians to get out of the building.
The AP condemned the attack, and asked Israel to put forward evidence. "We have had no indication Hamas was in the building or active in the building," it said in a statement.
In what Hamas called a reprisal for Israel's destruction of the al-Jala building, Hamas fired 120 rockets overnight, the Israeli military said, with many intercepted and around a dozen falling short and landing in Gaza.
Israelis dashed for bomb shelters as sirens warning of incoming rocket fire blared in Tel Aviv and the southern city of Beersheba. Around 10 people were injured while running for shelters, medics said.
In Israel, the conflict has created anger and polarization, with violence between communities in mixed Jewish-Arab towns. Synagogues have been attacked and Arab-owned shops vandalized, with Israel's president warning against a slide into civil war.
There has also been an upsurge in deadly clashes in the occupied West Bank. At least 15 Palestinians have been killed by Israeli troops in the West Bank since Friday, most of them during clashes.
(Additional reporting by Eli Berlizon in Ashkelon, Michelle Nichols in New York Editing by Raissa Kasolowsky and Frances Kerry)