Fresh fighting in Gaza between rival Palestinian groups Hamas and Fatah has left a Hamas commander dead and at least 30 men injured.
The clash took place in the southern town of Rafah, where a Fatah member died in a gun battle on Thursday.
Clashes between the two factions have killed more than 50 since mid-May.
The latest death came hours after Palestinian militants launched their first raid from Gaza into Israel for nearly a year.
Hundreds of Hamas and Fatah gunmen clashed on street corners and rooftops using rocket-propelled grenades and machineguns, Rafah residents told Reuters news agency.
The local hospital was so overwhelmed it had to send many of the wounded to neighbouring towns for treatment, medical officials said.
A ceasefire agreed by Hamas and Fatah in May has been under threat in the last week after a member of forces loyal to Fatah was killed.
Earlier on Saturday, Palestinian militants used an armoured jeep to burst through the Kissufim border crossing, and attacked a nearby Israeli army post, leading to a gun battle.
One Palestinian was killed. There were no Israeli casualties.
The attack was launched by two Palestinian militant groups, Islamic Jihad and al-Aqsa Martyrs' Brigade.
A spokesman for Islamic Jihad said they had planned to abduct an Israeli soldier but were foiled by the arrival of Israeli helicopter gunships.
The cross-border attack was the first since Palestinian gunmen abducted an Israeli soldier, Corporal Gilad Shalit, almost a year ago.