Waning U.S. influence and John Kerry's failed peace bid are hampering efforts to reach a Gaza truce, but America remains the sole power capable of brokering a deal to stop the fighting, analysts said.

Amid an unfortunate Arab power vacuum caused by Egypt's internal political upheavals, any ceasefire between Israel and Hamas still remains days away with neither side yet ready to bend, experts predicted.

Dozens of displaced Gaza families flooded into a U.N. school early Tuesday after Israel warned them to leave their homes, struggling to set up camp in a cramped, dirty courtyard. 

Hundreds of homeless Gazans were already living there, with this school in the northern town of Jabaliya packed to overflowing.

The only power plant supplying electricity to the Gaza Strip was knocked out of commission by Israeli shelling, deputy director of the energy authority in the Palestinian territory said Tuesday.

"Gaza's sole power plant has stopped working due to Israeli shelling last night, which damaged the steam generator and later hit the fuel tanks which set them on fire," Fathi al-Sheikh Khalil told Agence France Presse.

Iran's supreme leader Ayatollah Ali Khamenei Tuesday accused Israel of committing "genocide" in Gaza and called on the Islamic world to arm Palestinians fighting "the Zionist regime".

In a speech marking the Muslim festival of Eid al-Fitr, Khamenei said Israel was acting like a "rabid dog" and "a wild wolf" in acts that are causing a human catastrophe and which must be resisted.

The deputy head of the Higher Shiite Islamic Council, Sheikh Abdul Amir Qabalan, called on Tuesday for the support of the Palestinian people and for limiting Lebanon's woes.

In his Eid al-Fitr sermon, Qabalan said: “We should steer clear of strife.”

A nine-year-old girl was killed on Monday when a rocket hit the ground outside a house in Egypt's Sinai Peninsula, in an apparent attack targeting soldiers, security officials said.

Another girl, 10, was wounded in the blast south of the town of Sheikh Zuwaid in northern Sinai.

North Korea has denounced allegations that it supplied missiles to Hamas and material support to Hizbullah as "sheer fiction" and a "sinister" effort to link Pyongyang to Middle East disputes.

The rebuttal from the foreign ministry was carried in a statement late Monday by the North's official KCNA news agency.

Egypt on Monday condemned Israel for using what it said was "excessive force" against civilians in the Gaza Strip.

It also urged Israel and Hamas, the Palestinian movement that dominates the Gaza Strip, to abide by the "humanitarian truce" proposed by Cairo and backed by the United Nations to end the 21-day conflict.

Barack Obama's demand for an "immediate, unconditional" Gaza humanitarian ceasefire has strained already-tense U.S.-Israeli ties and put Benjamin Netanyahu in a tight spot with hardliners in his government, commentators said.

Analysts see the U.S. president's call on Sunday as an ultimatum to Netanyahu, as the Palestinian toll from Israel's 21-day offensive in Gaza neared 1,050.

Bloodshed in and around Gaza surged Monday as several children were killed in Israeli strikes on the Strip, hiking the Palestinian death toll from Israel's 21-day operation to 1,060.

It was a bloody start to the three-day Muslim holiday of Eid al-Fitr which began on Monday, with international demands for an end to the fighting falling on increasingly deaf ears.