Palestinian sources say Israeli troops have killed at least three Palestinians and wounded some 30 others during fierce gun battles in Ramallah.
Palestinians say Israeli soldiers entered the West Bank town after local residents discovered and attacked an undercover Israeli unit that had arrested an Islamic Jihad leader.
Also Wednesday, Palestinian hospital officials say unidentified gunmen shot three Hamas members in the Gaza town of Khan Younis. One later died of his injuries.
The shooting appeared to be the latest clash between Hamas and Fatah members battling for control of Palestinian security forces.
On Tuesday, Palestinian Prime Minister Ismail Haniyeh, a Hamas leader, told reporters the internal fighting will not be allowed to escalate into civil war.
The Palestinian security forces are currently led by the Fatah faction loyal to Palestinian Authority President Mahmoud Abbas.
Mr. Abbas says he plans to convene a meeting of all Palestinian factions later this week to address the deteriorating security situation, as well as the dire economic condition many Palestinians are facing.
Some information for this report was provided by AFP, AP and Reuters.