Palestinian leader Mahmoud Abbas has denounced an Israeli raid on a Palestinian refugee camp that killed five Palestinians.
Violence flared following Tuesday's completion of the most important stage of the limited withdrawal of settler from occupied Palestinian territories.
According to Palestinian witnesses, young Palestinians were sitting outdoors, chatting with a well-known militant leader in the Tulkarem refugee camp in the West Bank, when undercover Israeli troops jumped out of a Mercedes.
Witnesses said soldiers ordered everyone to stand up and shined a red laser at the group before opening fire. "A car came, and armed men got out and shot toward us. I was hit in the shoulder," said a 15-year-old witness. He said a gunfight followed, and several of his friends were wounded.
About 4,000 people attended a funeral for the five. Gunmen fired in the air, and many residents accused Israel of destroying the calm that prevailed during the Gaza pullout.
Mr Abbas blamed Israel for inciting the sudden escalation with its deadly raid in Tulkarem. "This murder intentionally aims at renewing the vicious cycle of violence," he said.
Palestinian fighters vowed to renew attacks on Israel, a move that would undercut the goodwill that resulted from an Israeli pullout from 25 Jewish settlements in Gaza and part of the West Bank.
Mr Abbas called on militant groups to use restraint and to hold their fire.