Members of Palestinian president Mahmud Abbas' Fatah party asked Israel to attack rival Palestinian movement Hamas in 2007, diplomatic cables leaked by whistleblower WikiLeaks show.
The latest batch of cables quote the head of Israel's Shin Bet security agency as telling US officials that "demoralised" Fatah officials in the Gaza Strip had asked for help against the growing strength of Hamas.
"They are approaching a zero-sum situation, and yet they ask us to attack Hamas," Shin Bet chief Yuval Diskin told US officials. "They are desperate."
He went on to praise his organisation's "very good working relationship" with Abbas' security service, which he said shared with the Shin Bet "almost all the intelligence that it collects."
"They understand that Israel's security is central to their survival in the struggle with Hamas in the West Bank," he said during the June 2007 meeting.
Revelations of such close collusion with Israel against fellow Palestinians is likely to embarrass Abbas and Fatah.
Hamas and Fatah have had tense relations for years, and resentment boiled over shortly after the Islamist group won elections in 2006. A year later, shortly after Diskin's comments in 2007, Hamas routed Fatah in bloody fighting in the Gaza Strip and seized control of the coastal enclave.
The leaked cables were part of a flood of US diplomatic files published online by WikiLeaks, angering and embarrassing governments around the world.