Palestinian leader Mahmoud Abbas (search) threatened to use "an iron fist" against anyone who violates a cease-fire with Israel, his toughest warning against militants since taking office in January.
In a speech to Palestinian police, Abbas also pledged to maintain quiet during the Israeli withdrawal from the Gaza Strip planned this summer.
"We have to give them a calm departure," he said, according to a summary of the speech published Thursday by the Palestinian government news agency Wafa.
Abbas has been under heavy pressure from Israel and the United States to rein in Palestinian militants, who had a relatively free hand under Abbas' predecessor, the late Yasser Arafat (search). But so far, Abbas has preferred to negotiate with the armed groups.
Abbas last month won the agreement of most militant groups, including Hamas (search) and Islamic Jihad (search), to observe a truce with Israel. While there has been a sharp drop in violence, militants have fired several rockets at Jewish settlements in Gaza and an Israeli border town in recent days.
One salvo landed near a large gathering of Israeli demonstrators in a Gaza settlement on Wednesday, lightly wounding one soldier. Early Thursday, Palestinian militants fired an anti-tank missile at a settlement and opened fire at an army base in Gaza, causing no injuries, the army said.
Abbas said such violence cannot be tolerated.
"Whoever wants to sabotage [the truce] with rocket fire or shooting must be stopped by us, even if that requires using force," Abbas said. "There is a national consensus regarding the calm, and whoever leaves this consensus will be struck by an iron fist."
Abbas didn't single out any specific militant group.
No one has claimed responsibility for the recent rocket attacks, although a tiny group, the Popular Resistance Committees (search), has said it opposes the cease-fire and is suspected by Israel of being behind some of the violence.
The biggest militant groups, Hamas and Islamic Jihad, have largely honored the truce. Hamas appears to be focusing its efforts on Palestinian legislative elections scheduled in July, though earlier this week it rejected Abbas' call to give up its weapons after the vote.
Hamas spokesman Mushir al-Masri said the group continues to honor the truce, but holds Israel responsible for any violence. "Hamas is committed to the calm declared by all the factions, but the world ... should realize that the problem is the Israeli occupation."
Israel, which captured the Gaza Strip and West Bank in the 1967 Mideast war, is planning to withdraw from Gaza and part of the West Bank in either July or August. Israeli military planners fear Gaza militants will step up attacks as the pullout approaches, trying to show that they are forcing the Israelis to leave.
Tens of thousands of Israelis opposed to the withdrawal plan demonstrated in Gaza's largest bloc of Jewish settlements Wednesday, but the event had lower-than-expected turnout.
A similar demonstration was scheduled Thursday in one of four West Bank settlements slated for evacuation. Israeli media said about 10,000 people were expected.
A hardline lawmaker's call for stiff resistance to the withdrawal at Wednesday's rally drew widespread condemnation, with officials accusing the legislator of incitement and encouraging violence against Israeli forces carrying out the evacuation.
Arieh Eldad, a member of the pro-settler National Union, urged mass resistance to the pullout, even if it means breaking the law.
"There must be resistance that includes willingness to go to jail," he said. "The days are nearing in which those who do not go to jail will bear a mark of disgrace."
Israeli media reported that Attorney General Meni Mazuz (search) is considering filing incitement charges against Eldad.