The fighting, which involved fire exchanges between the two rival Palestinian factions, took place in front of the Palestinian parliament building in Gaza City, the witnesses said.

Two people were said to be wounded in the armed clash.

The midnight incident came after Hamas deployed its so-called aiding force on Wednesday despite the decision to form the force was annulled by President Mahmoud Abbas last month.

Hamas Interior Minister Said Siam ordered on Wednesday new force to begin its duties to help the police maintain law and order in the Palestinian territories.

Siam said that the decision to launch the new force was made due to "mounting disorder and instability and increased attacks against the people."

After the 3,000-strong force deployed on Gaza streets on Wednesday, many stores closed down in fear of clashes between the pro-Hamas force and militants loyal to Fatah movement.