Palestinian officials say four people have been killed and 12 wounded in factional fighting in the Gaza Strip.
It was the worst fighting since the Islamic militant group Hamas and its rival faction, Fatah, agreed to a national unity government two months ago.
Sunday's flare-up started when gunmen killed a local commander of the Fatah-linked al-Aqsa Martyrs Brigades and his driver. The group blamed Hamas, which denied involvement.
Three people were wounded during the commander's funeral.
In another shooting, gunmen killed two men and wounded nine others in Gaza City. And masked gunmen abducted a Hamas official outside his home in Gaza City.
The tension in the Gaza Strip took place as Israel's Security Cabinet met to discuss a military response to continuing Palestinian rocket attacks. Officials decided against a major offensive in Gaza.
Israel's army says some 240 rockets have been fired at Israel since a ceasefire began five months ago.