Supporters of rival groups Hamas and Fatah have clashed with each other in the Gaza Strip amid a power struggle in the Palestinian Authority.
At least 15 people were injured in the clashes Saturday after students at separate Hamas and Fatah-run schools in Gaza City began throwing rocks at each other.
The violence stems from Hamas' controversial appointment of Jamal Abu Samhadana as chief of a new security branch made up of armed anti-Israeli factions.
Palestinian President Mahmoud Abbas of Fatah vetoed the Hamas plan to create the new security branch led by Samhadana, who is wanted by Israel for attacks against its citizens.
Hamas officials have said the decision would stand and accused Mr. Abbas of working with Israel and the United States to topple the new Hamas-led government.
Security has been a contentious issue since the radical Islamist group's landslide electoral win against Mr. Abbas' Fatah party.
Since taking office last month, Hamas has rejected all calls to renounce violence and recognize Israel's right to exist. The United States and European Union have withheld millions of dollars in direct aid to the Palestinian Authority. Both consider Hamas a terrorist organization.
Some information for this report was provided by AFP, AP and Reuters.