GAZA CITY, Gaza Strip, AP- Israeli artillery fire killed a Palestinian police officer and wounded 16 people in Gaza Sunday, as Israel escalated its retaliation for militant rocket strikes and put pressure on the new Hamas-led government that refuses to stop the attacks.

The shelling, which set a plastics factory ablaze and hit a house where seven people were wounded, was part of an Israeli offensive to stop the waves of rockets launched from Gaza into southern Israel. No Israelis were wounded in the rocket fire over the weekend.

Israeli air and military strikes have killed 15 Palestinians since Friday, including 13 militants and a child.

The stepped-up military strikes come less than two weeks after the Islamic militant Hamas — which rejects Israel’s right to exist — took control of the government. Over the weekend, Israel began for the first time firing artillery at rocket-launching sites in populated areas.

Acting Israeli Prime Minister Ehud Olmert said the military has been given a free hand to act against militants.

“Security forces will act decisively against anyone who fires Qassam (rockets), or anyone who will deal or deals in terror,” Olmert said before the weekly meeting of the Cabinet, which was to discuss a more detailed policy toward Hamas. “There are no restrictions on security forces in the event they identify danger.”

Hamas’ military wing condemned the “dangerous escalation” and vowed revenge.

“We warn the government of this monstrous entity against committing more crimes, because this will provoke more destruction and escalated military attacks against them and their people,” the military wing said on Hamas’ Web site.

The police officer killed Sunday, Yasser Abu Jarad, 28, was trying to evacuate colleagues from a makeshift military post when a shell hit his car and killed him, Palestinian security officials said. The army said it had warned Palestinian security officers posted near launching sites that they could be in danger from Israeli retaliation.

Israel has launched 900 artillery shells at northern Gaza since Thursday, the army said. During that time, the militants fired 10 rockets at Israel.

One shell Sunday hit a house in the northern town of Beit Hanoun, wounding at least seven people, Palestinian security officials said. Farmers evacuated their cows because of nearby shelling. Shells hit several farms and two cows were seen bleeding. Students also evacuated a school near the border with Israel and an ambulance waited in the street in case of an emergency.

“If the Israelis thought this policy would work with the Palestinians, they are mistaken, because violence and escalation will bring more violence and will not lead to calm,” said Osama Inesu, a 39-year-old police officer.

While Israel has been pressuring Hamas with military strikes, the U.S. and European Union cut off of hundreds of millions of dollars in desperately needed aid to the Palestinian Authority because of Hamas’ refusal to recognize Israel, renounce violence and accept existing peace accords.

Israel suspended the monthly transfer of some $55 million in taxes it collects on behalf of the Palestinian Authority shortly after Hamas won Jan. 25 Palestinian parliamentary elections.

In an interview published in The Washington Post on Saturday, Olmert said he would not hold peace talks with the Palestinians’ moderate president, Mahmoud Abbas, because Abbas has lost authority since Hamas’ rise to power.

Olmert has said he will unilaterally pull out of large parts of the West Bank while annexing large Jewish settlement blocs in the territory if Hamas does not change its stance toward Israel and peace talks.

Hamas has said repeatedly it will not revise its positions, though some group leaders have hinted at a readiness to moderate.

Abbas, meanwhile, told the British newspaper The Guardian in an interview published Sunday that Hamas has begun to realize that it cannot govern without the world’s recognition.

“You may notice some confusion in their political positions,” Abbas told the newspaper. “If Hamas does not change, nobody will deal with them. … They came to understand it.”

Israeli police and rescue services, meanwhile, went on high alert Sunday to prevent Palestinian attacks ahead of the weeklong Passover festival, which starts at sundown Wednesday. A suicide bombing at a festive Passover meal at a hotel killed 29 people four years ago.