Israel said it knew of no casualties from a long-range Palestinian rocket salvo on Tuesday that Hamas said targeted cities including central Tel Aviv and Jerusalem, as well as Haifa in the north.
"We are not getting reports of casualties from any of the impact areas," the chief military spokesman, Brigadier-General Motti Almoz, told Israel's Channel 10 television. He did not elaborate on the locations.
Hamas said it fired a rocket at the city of Haifa, northern Israel, in what would be the longest-range such Palestinian attack from the Gaza Strip.
Earlier, the army said that Israeli soldiers killed four Palestinian gunmen who slipped into southern Israel by sea from the Gaza Strip.
Hamas, the dominant force in Gaza, claimed responsibility for the infiltration at Zikim beach, which occurred as Israel bombed the Palestinian enclave with the stated purpose of quelling cross-border rocket fire.
Hamas said it was in telephone contact with the commander of the squad that stormed Zikim and that he was exchanging fire with the army.
Lieutenant-Colonel Peter Lerner, an Israeli military spokesman, said four gunmen were killed by combined fire from troops, the air force and the navy. Israeli forces were still searching the area. He did not say whether the gunmen had swum in or landed by boat.
Lerner said an Israeli soldier had been wounded in the incident, which he described as rare. The Israeli military keeps Gaza under tight naval cordon.
Meanwhile, a military source said that Israel shot down a rocket fired at its commercial capital Tel Aviv.
Live television showed a double-burst of smoke in the clear blue skies above Tel Aviv after air raid sires sounded.
The military source said Israel's Iron Dome interceptor shot down the projectile fired by Palestinians, hours after Israel intensified its bombing campaign in Gaza in a declared bid to halt rocket fire pouring into the south of the country.
This comes after at least 11 Palestinians were killed and scores wounded in an Israeli attack on a house in the Gaza Strip, the Palestinian Interior Ministry said.
Local residents said the dwelling belonged to the family of a Hamas member and that the casualties occurred when it came under attack for the second time on Tuesday.
After the first strike, people had gathered on its roof as "human shields", hoping their presence would deter a second strike, the residents said. The Israeli military had no immediate comment.
Also on Tuesday, Israel bombarded dozens of targets in the Gaza Strip, stepping up what it said might become a long-term offensive against Islamist Hamas.
Following the worst outbreak of violence along the Gaza frontier since an eight-day war in 2012, the Israeli military said a ground invasion of the enclave was possible, though not imminent, and urged citizens within a range of 40 km (24 miles) of the coastal territory to stay close to bomb shelters.
The Israel-Gaza border heated up last month after Israel's arrest of hundreds of Hamas activists in the occupied West Bank, where three Israeli youths went missing on June 12.
More than 200 rockets have been launched at Israel from the Gaza Strip, the military said, since Israel mounted the dragnet while searching for the teens who were found dead last week.
Israel has accused Hamas militants of killing them. In a suspected revenge attack, a Palestinian teen was abducted in East Jerusalem last Wednesday. His charred body was found in a forest and six Israeli suspects have been arrested.
The Israeli military said that in the past 24 hours, more than 100 rockets had been fired at Israel, a sharp increase.
Some were intercepted by the Iron Dome anti-missile system, but two people were wounded by shrapnel.
In this regard, the Israeli government gave the military permission to mobilize up to 40,000 additional reservists as it steps up an offensive in the Gaza Strip. The Israeli military said there were no immediate plans to call up the reservists, but the order was a contingency if the offensive needs to be expanded. Israeli officials say the open-ended operation could go on for some time.
Meanwhile, Hamas' armed wing, threatened an "earthquake" in response to Israel's attacks, but a Palestinian source close to the group said it was ready to restore calm if Israel met conditions, including a prisoner release.
The Israeli military, announcing it had launched "Operation Protective Edge", said it targeted about 50 sites in aerial and naval assaults overnight and resumed air strikes on Tuesday morning after rockets were fired at southern Israeli towns.
Hamas has been reeling over an Egyptian crackdown on most of the estimated 1,200 cross-border smuggling tunnels run by the group, which Egypt says are used to take weapons into the Sinai Peninsula.
Positions
The Secretary General of the Arab League, Nabil al-Arabi called on Tuesday for an urgent meeting to be held by the UN Security Council on the backdrop of the deadly Israeli offensive on the Gaza Strip, Agence France Press said.
In turn, France's foreign ministry, commenting on violence between Israeli troops and Palestinians in the Gaza Strip, urged all parties to exert restraint.
REUTERS
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