Gaza City, Gaza Strip ? Israel sent fuel to Gaza’s power plant on Tuesday, easing its five-day blockade of the Palestinian territory amid growing international concern about a humanitarian crisis.

The U.S. warned Israel not to add to the hardship for ordinary Palestinians but blamed the problem on Gaza’s Islamic Hamas rulers. Israel imposed the siege in response to increasing rocket attacks on its border communities by Gaza militants.

Despite the easing of the closure, Palestinian militants fired 19 rockets toward Israel on Tuesday, the military said, up from just two on Monday.

The lights were back on in most of Gaza City by Tuesday afternoon after a blackout that lasted almost two days. But Gazans still vented their anger.

Hundreds of Hamas supporters briefly broke through the Gaza-Egypt border and clashed with Egyptian riot police who fired in the air, injuring 70 people on both sides. The protesters hurled insults at Egyptian President Hosni Mubarak, calling him a coward.

Hours later, masked Palestinian gunmen detonated explosives early Wednesday next to the wall at the Gaza-Egypt border, causing several holes in the barrier, witnesses said. Dozens of residents waited to cross in Egypt as Hamas forces gathered on the scene.

On the other side, Egypt deployed troops to block any infiltration attempts from Gaza. They shined spotlights on to the gaps, but it didn’t appear as if anyone had immediately crossed.

Israel and Egypt have banned most crossings in and out of Gaza since Hamas seized control of the territory in June. Egypt has kept its border closed, tacitly supporting Israel’s blockade out of fear of a spillover of Hamas-style militancy to its territory.

Pictures of blacked-out Gaza City, children marching mournfully with candles and people lining up at closed bakeries evoked urgent appeals from governments, aid agencies and the U.N. for an end to the closure, though Israel maintained all along that Hamas created an artificial crisis.

The Defense Ministry ruled late Tuesday that 60,000 gallons of diesel fuel will be transferred into Gaza daily, but the crossings will remain closed to other goods and people until further notice.