The Israeli army has admitted that three Palestinian children killed by Israeli fire in the Gaza Strip Wednesday were simply playing near rocket launchers and had nothing to do with Palestinian militants.

The army said Friday an internal investigation into the incident has revealed that the children were not involved in hostile activity.

The three children, all age 12 or younger, died Wednesday after Israeli soldiers opened artillery fire on a field in northern Gaza. After the incident, the Israeli army had expressed "sorrow" at what it called terror organizations' use of teenagers in terror attacks.

Friday in Gaza, at least eight people - including at least one foreign journalist - were injured by what appeared to be stun grenades as Hamas security personnel dispersed a protest by supporters of the rival Fatah faction.

After prayer meetings in Gaza City and Rafah held to protest the Islamist faction, Hamas security men fired shots into the air and beat and arrested protesters.

During a similar incident last Friday, Hamas members fired into the air to disperse a demonstration in Gaza City by thousands of Fatah supporters. Hamas security forces attempted to prevent journalists from covering the demonstration, and troops broke the cameras of several news photographers.

Some information for this report was provided by AFP and AP.