* Militants warn will fire rockets at Israel's main airport
* Netanyahu does not rule out ground invasion into Gaza
* 115 Palestinians, many civilians, killed by Israeli fire
* Gaza militants launch rocket salvoes deep into Israel (Updates death toll, military on latest activities)
By Nidal al-Mughrabi and Ori Lewis
GAZA/JERUSALEM, July 12 (Reuters) - Israel pounded Palestinian militants in the Gaza Strip on Saturday for a fifth day, killing nine people including two disabled women according to medics, and showed no sign of pausing despite international pressure to negotiate a ceasefire.
Asked if Israel might move from the mostly aerial attacks of the past four days into a ground war in Gaza to stop militant rocket fire, Prime Minister Benjamin Netanyahu replied: "We are weighing all possibilities and preparing for all possibilities."
"No international pressure will prevent us from acting with all power," he told reporters in Tel Aviv on Friday, a day after a phone call with U.S. President Barack Obama about the worst flare-up in Israeli-Palestinian violence in almost two years.
Washington affirmed Israel's right to defend itself in a statement from the Pentagon on Friday. But Defence Secretary Chuck Hagel told Israeli Defence Minister Moshe Ya'alon he was concerned "about the risk of further escalation and emphasized the need for all sides to do everything they can to protect civilian lives and restore calm", a Pentagon statement said.
Two disabled women were killed and four others wounded and in serious condition when an Israeli tank shell struck a rehabilitation centre in the eastern part of Gaza City, Palestinian medics said. An Israeli military spokeswoman said she was checking for details on why the centre was targeted.
Three militants and four other people including a 65-year-old man were killed by air strikes early on Saturday, doctors in the densely populated sliver of coastal territory said.
Residents said a mosque in the central Gaza Strip was bombed to rubble. The military said it had housed a weapons cache. Graffiti scrawled on one of the mosque's blasted walls read, "We will prevail despite your arrogance, Netanyahu."
In Israel, a Palestinian rocket seriously wounded one person and injured another seven when it hit a fuel tanker at a service station in Ashdod, 30 km (20 miles) north of Gaza. Islamist militants in Gaza warned they would launch rockets at Tel Aviv's main international airport and warned airlines to stay clear.
Gaza medical officials said at least 76 civilians, including 24 children, were among 115 people killed so far in the aerial bombardments on the narrow 40-km-(25-mile)-long, sandy strip into which nearly 2 million people are packed.
Western-backed Palestinian President Mahmoud Abbas, based in the Palestinian self-rule area of the Israeli-occupied West Bank, urged the United Nations Security Council to order an immediate ceasefire.
But Israel said it was determined to end cross-border rocket attacks that intensified last month after its forces arrested hundreds of activists from the Islamist Hamas movement in the West Bank after the abduction there of three Jewish teenagers who were later found killed. A Palestinian youth was then killed in Jerusalem in a suspected revenge attack by Israelis.
Israel's campaign "will continue until we are certain that quiet returns to Israeli citizens," Netanyahu said. Israel had hit more than 1,000 targets in Gaza and there were "more to go."
Israel's army chief, Lieutenant-General Benny Gantz, said his forces were ready to act as needed - hinting at readiness to send tanks and ground troops across the barbed-wire boundary into Gaza, as Israel last did for two weeks in early 2009.
"We are in the midst of an assault and we are prepared to expand it as much as is required, to wherever is required, with whatever force will be required and for as long as will be required," Gantz told reporters.
The Israeli military issued a daily summary on Saturday, saying it had managed to strike at "10 terror operatives, six of whom were directly involved in the launch of rockets at Israel at the time of the targeting".
The statement added that 68 rocket launchers, 21 militant compounds and 18 weapons-manufacturing facilities had been hit and militants had fired almost 700 projectiles into Israel.
CALL FOR CEASEFIRE
Abbas, who agreed a power-sharing deal with Gaza's dominant Hamas in April after years of feuding, called for international help. "The Palestinian leadership urges the Security Council to quickly issue a clear condemnation of this Israeli aggression and impose a commitment of a mutual ceasefire immediately."
After the failure of the latest U.S.-brokered peace talks with Israel, Abbas's deal with Hamas angered Israel.
The rocket salvoes by the Islamist movement and its allies, some striking more than 100 km (60 miles) from Gaza, have killed no one so far, due in part to interceptions by Israel's partly-U.S. funded Iron Dome aerial defence system.
But racing for shelter has become a routine for hundreds of thousands of Israelis, and some 20,000 reservists have already been mobilised for a possible thrust into Gaza, the army says.
Tel Aviv's Ben-Gurion Airport has been fully operational since the Israeli offensive began and international airlines have continued to fly in, with no reports of Gaza rockets - largely inaccurate projectiles - landing anywhere near the facility, inland from the Mediterranean coastal metropolis. The airport is within a zone covered by Iron Dome.
Fire was also exchanged across Israel's northern border on Friday. Lebanese security sources said two rockets were launched into northern Israel but they did not know who was responsible. Israel responded with bursts of artillery. Palestinian groups in Lebanon have often sent rockets into Israel in the past.
Israel's Gaza operation is the deadliest since November 2012, when around 180 Palestinians and six Israelis were killed during an Israeli air campaign to punish Hamas for missile attacks. That conflict was eventually halted with mediation from Egypt, then governed by Hamas's Muslim Brotherhood allies.
But Egypt, now ruled by the Brotherhood's enemies, is locked in a feud with Hamas over the group's alleged support for jihadi militants in Egypt's Sinai desert - something Hamas denies. Cairo said on Friday its "intensive efforts" with all sides to end the warfare has met only "intransigence and stubbornness".
Izzat El-Risheq, a Hamas official told Arab television Al-Hadath "there are efforts for a ceasefire", but demanded Israel stop its offensive before any deal could be reached.
If Israel launches a ground invasion of Gaza, it would be the first since a three-week war in the winter of 2008-09, when some 1,400 Palestinians and 13 Israelis were killed. (Additional reporting by Allyn Fisher-Ilan and Dan Williams in Jerusalem and Ali Abdelatti in Cairo, Editing by Mark Heinrich)