Gaza City, Gazy Strip ? Israeli Prime Minister Ehud Olmert stepped up pressure on the Palestinian government Sunday, telling his military to “do all it can” to free an abducted soldier and hinting Israel might arrest more Hamas leaders.

Coming just hours after an Israeli airstrike blasted offices of the Palestinian prime minister, Mahmoud Abbas, Olmert’s threat signaled the government was losing patience with diplomatic efforts to end the crisis and preparing for a possible escalation of its military offensive.

Israel shelled northern Gaza early today, slightly wounding one person in a house on the outskirts of the town of Beit Hanoun, Palestinians said. The military confirmed artillery was fired in the area.

Israeli aircraft, gunboats and artillery have pounded Gaza since troops and tanks took up positions in the south of the coastal strip Wednesday. The operation is aimed at pressuring Palestinians to free Cpl. Gilad Shalit, the Israeli soldier abducted a week ago. Five Palestinian fighters had been reported killed, four of them Sunday.

Palestinian officials had warned Saturday that a shortage of fuel threatened to shut down generators used to pump water and power hospitals.

Israel on Sunday reopened the main cargo crossing with Gaza to allow 50 trucks of food, medical supplies and fuel into Gaza from Israel, Israeli officials said. Trucks carrying diesel fuel, gasoline and natural gas also began entering northeastern Gaza through the Nahal Oz border crossing.

“I take personal responsibility for what is happening in Gaza. I want nobody to sleep at night in Gaza. I want them to know what it’s like,” Olmert told his Cabinet. “People are saying it’s uncomfortable. It will be uncomfortable, (but) nobody dies from being uncomfortable.”