Two civilians, one a two-year-old boy, were among those killed, according to Palestinian medical sources.

The clashes erupted after weeks of relative calm and renewed efforts to form a national unity government.

Hamas and Fatah said they were suspending talks after the violence, which was still continuing early on January 27.

Reports from Gaza City say Hamas and Fatah gunmen exchanged mortar fire and grenade attacks outside a security compound.

More than 40 people have died as a result of a power struggle between supporters of the Hamas-led government and Palestinian Authority President Mahmoud Abbas' Fatah faction since mid-December.