Samhadana's group, the Popular Resistance Committees, has launched dozens of homemade rockets at Israel in recent weeks. It also is suspected of involvement in the October 2003 bombing in Gaza of a U.S. Embassy convoy, which killed three American security guards.

U.S. State Department spokesman Sean McCormack said the formation of the new Palestinian police force showed "the true nature and the true tactics of this particular Hamas-led government." The United States will still hold the Palestinian Authority responsible for stopping terror attacks, he said.

Hamas, which is sworn to Israel's destruction, has largely observed a cease-fire with Israel since February 2005. But since taking office last month, the Hamas leadership has said attacks carried out by other groups, including Monday's suicide bombing that killed nine, are justified.

Israel says it holds Hamas responsible for all the violence, though defense officials are still weighing whether to begin attacking Hamas targets directly.

Galant, the Israeli commander, said patience is wearing thin with Hamas. He said the army is preparing for a range of responses to the rocket fire.

"It could be anything from a partial occupation of the Gaza Strip to a full occupation," he told Maariv, adding that the plans have been approved by senior officials, including Defense Minister Shaul Mofaz.

Israel has responded to the rocket attacks with airstrikes and artillery fire on suspected launch sites. Israeli security officials concede it is very difficult to halt the primitive weapons, which are airborne for just 15 to 20 seconds and are hard to detect.

Israel already has made two brief incursions into Gaza in recent days to search for explosives. But defense officials said the odds of a large-scale operation or full occupation are slim because of financial and political constraints.

"I wouldn't want to reach that situation, but if it's forced upon us we have a plan to occupy the strip," Galant said. "We are in advanced stages of preparing forces for readiness. There is a practical plan and there are forces which are designated for specific operations and are training for them."

Israel is reluctant to go back into Gaza after spending hundreds of millions of dollars to withdraw and overcoming staunch internal political opposition. In addition, Israel is pleased with the international pressure on Hamas and fears military action could jeopardize that.

Galant's threat of a reoccupation could in part be aimed at an Israeli public outraged over the rocket fire. It could also be meant to put pressure on Hamas to halt the attacks.

Hamas defeated the long-dominant Fatah Party in January legislative elections, and its new Cabinet was sworn into office late last month.

The appointment of Samhadana was the latest step in a growing power struggle between Hamas and Abbas, a moderate who leads the Fatah party.

Soon after the new Cabinet was sworn in last month, Abbas appointed a longtime ally to head three security services that were supposed to fall under Hamas command. Abbas controls several other security services directly.