UPDATED: PALESTINIAN CIVIL WAR UPDATE

Hamas kills 8 at Gaza border crossing (AP)
GAZA CITY, Gaza Strip - Hamas gunmen on Tuesday ambushed rival Fatah forces near a key crossing along the Israeli border, killing eight people in the deadliest battle yet in three days of factional fighting.

The incident briefly drew Israeli gunfire, threatening to drag Israel into the conflict at a time when its prime minister said his country was ready to discuss an Arab initiative that offers peace for land.

At least 20 people, including 11 total on Tuesday, have died in the fighting, bringing life in Gaza to a standstill and pushing the fragile Palestinian unity government closer to collapse. Hamas and Fatah formed the union to end months of violence.

Tuesday's fighting began when Hamas gunmen approached a training base used by Fatah forces that guard the crossing, officials said. The base was set up in part by a U.S. security team sent to train Palestinians on how to check cargo and bags at crossings.

The Islamic militant Hamas force attacked the base with rockets, rocket-propelled grenades and mortars, said Ahmed al-Kaisi, spokesman for the pro-Fatah Presidential Guard: "We consider this a serious provocation and a crime committed in cold blood."

When another Fatah security unit arrived to provide backup, they were ambushed by Hamas gunmen, witnesses said.

A jeep full of security men that came under fire veered off the road and crashed. Hamas forces then riddled it with gunfire, said one witness, who gave only his first name, Jamil, out of fear for his safety.

Hospital and security officials said eight men were killed in the ambush.

See also Anarchy Wins in Gaza - Danny Rubinstein
Hani al-Kawasmeh's resignation as the PA interior minister - the person responsible for internal security - dealt a mortal blow to efforts to prevent chaos in Gaza and endangers the unity government's continued existence. Most of the clashes of the past few days have been between Hamas' Operational Units (most of which are affiliated with the organization's military wing, Iz a-Din al-Qassam) and two security services headed by Fatah men, the Preventive Security Service and General Intelligence (which are affiliated with Fatah's military wing, the Al-Aqsa Martyrs' Brigades). Gaza residents and journalists say that the organization, discipline and weapons of the Hamas forces are far superior to those of the Fatah groups. (Ha'aretz)

See also Gaza on the Verge of Civil War - Andrew Lee Butters
The area evacuated by Israel in 2005 is well on its way to becoming a kind of seaside Falluja, a safe haven and training ground for extremists of all kinds. Aid workers recently returned from Gaza describe a city breaking down into tribal and gang formations, much like Iraq. The fact that these groups can act with impunity is clear in the ongoing captivity of BBC journalist Alan Johnston, who was kidnapped in March, and has been held despite the fact that his release has been demanded by the top leadership of both Fatah and Hamas. (TIME)

UPDATE: Death toll in Hamas-Fatah clashes up to 12; Palestinian PM to call for Hamas-Fatah cease fire; Gaza: 2 children injured in Hamas-Fatah clashes