Israel Blocks Supplies, Steps Up Gaza Airstrikes

About 60 of the 197 megawatts of electric power that Gaza requires are generated by its single power plant, which depends on the now-interrupted delivery of fuel.

Israel, which declared Gaza a "hostile entity" in September, has closed the checkpoints before, usually for several days at a time. Dror said the latest closing was a military decision. Intent on stopping the rocket attacks, Israeli authorities had considered launching a ground offensive into Gaza or heavily bombing areas where Palestinian fighters share space with civilians, Dror said. Authorities decided against both of those options to minimize casualties, he said.

People always look "for the responsibility of Israel" concerning the worsening situation of the Gaza population, Dror said. "I think it's time to look for the responsibility of Hamas."

For Friday and Saturday, Dror said, Israel would allow only Palestinians with urgent medical needs in and out of Gaza.

Meanwhile, the escalation of attacks on Gaza triggered some of the first overtures between the two Palestinian factions since they clashed last summer in Gaza.

Abbas called senior Hamas leader Mahmoud Zahar, whose son was killed Tuesday by the Israeli strike, to express condolences. It was the first contact between the president and top Hamas officials since June, said Mustafa Barghouti, an independent Palestinian politician who met with Abbas on Friday.

Fatah officials also reportedly attended the young man's funeral.