Palestinians flee their homes to take shelter at the United Nations school in Gaza City, Sunday, July 13, 2014. Israel briefly deployed ground troops inside the Gaza Strip for the first time early Sunday as its military warned northern residents to evacuate their homes, part of a widening campaign against militant rocket fire that's seen more than 160 Palestinians killed. Israel accuses Hamas of using Gaza's civilians as human shields by firing rockets from there. Critics say Israel's heavy bombardment of one of the most densely populated territories in the world is itself the main factor putting civilians at risk. (AP Photo/Hatem Moussa) (AP2014)

Some 4,000 Palestinians sought refuge Sunday at U.N. offices in Gaza after at least 45 people died and 131 were wounded over the past 24 hours in intense Israeli attacks on the densely populated coastal strip.

Some 166 people have died - among them 23 children - and more than 1,100 have been wounded in the six days so far of the third Israeli offensive against Gaza since the Islamist Hamas movement assumed control in the zone in 2007, Chris Gunnes, the spokesman for the U.N. agency for Palestinian refugees, or UNRWA, said.

"The situation in Gaza continues to be devastating and unpredictable. Thousands of terrorized people are trying to flee from the attacks and find refuge at UNRWA installations. We've opened eight schools and just today about 4,000 people have sought refuge," Gunnes said.

"The number is growing as the day progresses. Six of those schools are in Gaza City," the U.N. spokesman said.

Gunnes once again urged all parties to put an end to the hostilities, protect civilians and respect international law.

Military spokesmen in Israel, meanwhile, said that a rocket fired by Palestinian militias from the Gaza Strip on Sunday hit the Israeli city of Haifa, 150 kilometers (93 miles) away for the first time.
The rocket was part of a salvo of three missiles fired at mid-afternoon, with the other two being launched at the Tel Aviv metro area but both of which were intercepted and destroyed by Israel's Iron Dome missile defense system.

Haifa, located in northern Israel, is one of the country's two most important ports and along the bayshore there, north of Mt. Carmel, are many petrochemical plants and facilities, making the area a key target for Palestinian militias. EFE