Jerusalem ? Violence flared Monday on the eve of a planned meeting between Israeli Prime Minister Ariel Sharon and Palestinian Authority President Mahmoud Abbas, dampening what had already been low expectations for their first face-to-face encounter in more than four months.

Gunmen from the militant Palestinian group Islamic Jihad killed a Jewish settler in a roadside ambush in the West Bank. And Israel said it narrowly prevented a suicide attack by a young Palestinian woman who was on her way from the Gaza Strip to Israel for medical treatment.

Also Monday, Israeli troops shot and killed a 17-year-old Palestinian youth and wounded a second as the pair approached the border fence between Gaza and Israel. Relatives said they believed the teenagers, both from the same impoverished Bedouin clan, were trying to slip into Israel to find work.

Israeli and Palestinian officials acknowledged that the recent upsurge in violence was likely to make security matters the centerpiece of the Sharon-Abbas talks, which are to take place at the prime minister’s residence in Jerusalem.

After Abbas was elected in January to replace the late Yasser Arafat, there were widespread expectations that the Israeli and Palestinian leaders would move quickly to try to develop a personal rapport that would contrast with the mutual loathing expressed by Sharon and Arafat.

But Sharon and Abbas have not met since a Feb. 8 summit in Sharm el-Sheikh, Egypt.

Both sides head into the talks with a sense of grievance. Palestinians say Israel has granted far too few concessions, such as troop pullbacks and prisoner releases, that could have bolstered Abbas’ popularity among Palestinians.

For Israel, the deteriorating security situation is taking on greater urgency because of its planned pullout from Gaza scheduled to begin in two months. Israel, which is to relinquish 21 Jewish settlements in Gaza and four smaller ones in the northern West Bank, is extremely reluctant to give the appearance of withdrawing under fire.

Abbas extracted an informal truce accord earlier this year from militant groups, and the calm that has largely held except for the militants’ firing of rockets and mortars at Jewish settlements in Gaza.