JERUSALEM — Israel is skeptical about the Palestinian Authority's tentative measures against terrorism — and is taking matters into its own hands.

Both Israeli Defense Minister Shaul Mofaz and Israel's army chief of staff, Moshe Ya'alon, said this week that the measures the Palestinian Authority is taking in the Gaza Strip are not substantial.

Ya'alon and others said that the Palestinian Authority's arrests of weapons smugglers and the closing of arms-smuggling tunnels from Egypt into the Gaza Strip are not the beginnings of a true crackdown on terrorism. They said the moves were a tactical ploy to reduce American pressure on the Palestinian Authority and ward off further Israeli military operations.

That move apparently failed.

On Tuesday, a Palestinian bystander was killed in a failed Israeli missile attack in the Gaza Strip. More than a dozen people were wounded in Tuesday's strike near the Jabaliya refugee camp that targeted a member of Hamas' military wing, who reportedly was traveling in a car that was hit.

After the attack, dozens of people gathered around the car's remains, calling for revenge.

On Sunday, however, Israel hit its target.

Missiles fired from Israeli helicopter gunships at targets in Gaza City killed four.

Two of those killed were Hamas officials, including Ahmed Shatiwi, a senior member of Hamas' military wing, who was commander of the terrorist group's Kassam rocket operators.

Meanwhile, Yasser Arafat appointed his former loyalist and security chief, Jibril Rajoub, as the Palestinian national security adviser. The move is seen as another attempt by Arafat to redirect power away from Palestinian Authority Prime Minister Mahmoud Abbas.

Rajoub, the former head of Palestinian Authority security in the West Bank, told The Associated Press that his main goal would be to reorganize the Palestinian security forces, but did not say whether he would crack down on terrorists.

On Tuesday, the United States criticized the appointment, saying it undermined both Abbas and the U.S.-backed "road map" peace plan.

White House spokeswoman Claire Buchan said the United States believed that the Palestinian security services need to be consolidated under Abbas and Security Minister Mohammed Dahlan.

"That is the way forward," Buchan said.

Officially, Israel and the Palestinians continue to back the American-initiated "road map" peace plan. Indeed, both parties claim the breakdown stems from the other side's failure to implement its obligations under the road map, and both maintain that their new moves are designed to force more scrupulous execution.

Some critics, however, say the flaw is not in the failure to implement the road map but in the plan itself, and they are calling for a new approach. Former Israeli Prime Minister Ehud Barak, never a fan of the road map, has revived his call for a unilateral Israeli withdrawal from the West Bank and Gaza Strip.

Israel, however, remains committed to the plan — and aides say Prime Minister Ariel Sharon hopes the renewed policy of targeting Hamas leaders will help get the plan back on track.

Critics charge that the targeted killings are a deliberate ploy to undermine a peace plan Sharon never wanted, but his aides claim the strikes make clear to the Palestinian Authority what will happen if it continues to evade a confrontation with Hamas. Moreover, Sharon aides say, knowing they are targets could convince Hamas leaders to suspend hostilities.

The policy of striking at Hamas leaders has revived the debate in the Cabinet and the defense establishment over what to do about Arafat — who, Israeli officials say, is every bit as much a supporter of terrorism as the Hamas leaders, and more of a thorn in the side of Abbas.

Foreign Minister Silvan Shalom and Finance Minister Benjamin Netanyahu support expelling Arafat, and the government is preparing an "Arafat file" so that it will be in a position to explain any action it may decide to take against him.

Some Israeli Cabinet ministers and ex-generals now speak openly of assassinating Arafat. Maj. Gen. Yom-Tov Samya, a former head of the army's southern command, declared on Israel Radio on Monday that after some short-term chaos, the Palestinian people — and some Arab governments — would thank Israel for removing Arafat from the scene.