JERUSALEM (AP) _ Palestinian leader Yasser Arafat's police warned Muslim militants Wednesday that they would crack down on anyone carrying weapons in public or attacking Israelis.

But Israel Radio reported that Prime Minister Yitzhak Rabin called the action against the Islamic Resistance Movement, or Hamas, an ineffective media stunt. Rabin was quoted as saying it didn't amount to a concentrated effort to halt violence in the newly autonomous Gaza Strip and Jericho region.

In Gaza, Israeli troops shot and killed a 17-year-old Palestinian trying to sneak through the border fence into Egypt. The army said the youth ignored orders to stop. Palestinian and Israeli liaison officers were investigating the shooting.

While the Palestinians have been given self-rule in Gaza, Israel retains control over external security and borders.

Arafat's warnings came through Col. Tawfiq Jaber, the head of Palestinian police intelligence in southern Gaza, where underground armed Hamas cells are concentrated.

''He told us he didn't want to see anyone masking their face or carrying weapons,'' said Ahmed Kourd, a Hamas leader who met with Jaber.

Ahmad Nakhleh, another Hamas member who attended the meeting, said Jaber ''told us he was willing to sacrifice 100 of his men to implement the policy of the Palestinian authority on the Gaza Strip.''

Hamas leaders said they would not be intimidated by Arafat's latest admonition.

''The warning from Arafat will not have any influence on the Hamas movement,'' prayer leader Mohsen Abu Aita said. Hamas ''has strong support among the people.''

He said people who attack Israelis are considered heroes.

Vehicles drove through Gaza City on Wednesday night, using loudspeakers to announce that members of the PLO's mainstream Fatah organization were also banned from carrying guns in public. Only full-time security personnel were allowed to go armed, the announcements said.

A Palestinian police spokesman, speaking on condition of anonymity, said that all of the approximately 40 Hamas activists detained in house searches over the past three days had been released.

Israeli radio quoted Rabin as telling religious legislators that the Palestinian police's moves against Islamic activists were more political than effective arrests.

Rabin's spokesman Oded Ben-Ami would not confirm the remarks, made in a closed meeting with the legislators from the National Religious Party.

Israel itself moved against at least two Hamas activists.

Relatives said Yasser Rajoub, brother of the head of Palestinian security in Jericho, was arrested at his home in a West Bank village near Hebron.

Rajoub, 35, was arrested by Israeli soldiers and intelligence agents who searched his home Tuesday night, the relatives said.

Israeli troops also arrested Hamas activist Khaled Salibi at an army checkpoint near the junction where an Israeli civilian was killed and six wounded in two attacks Sunday, Israeli radio reports said.

The army would not comment on either arrest.

In Alexandria, Egypt, top Palestinian negotiator Nabil Shaath rejected Israeli criticism that the self-rule authority was not doing enough to stop Hamas.

''You have been ruling for 27 years with iron and fire and you did not succeed in stopping these operations, so how are we going to stop them?'' Shaath said.

Israel has said the peace talks can continue but no new agreements will be implemented until the Palestinians improve their security record. Five Israelis have been killed in dozens of attacks since the Palestinians took control in May.