AMMAN, August 3, 2008 (AFP) - Jordan's King Abdullah II warned visiting Palestinian president Mahmud Abbas on Sunday that Palestinian infighting threatens their efforts to form an independent state, the palace said.

'Continued factional infighting harms the Palestinian cause and threatens efforts to help establish an independent Palestinian state,' the king said according to a palace statement.

The king also 'expressed concerns about developments in the territories,' saying that the Palestinians 'should resort to dialogue to resolve their differences.'

'Palestinian unity is key to tackling the current challenges,' he added.

Israel on Sunday began returning Fatah members who had fled deadly clashes in the Gaza Strip to the Hamas-ruled territory following a request by Abbas.

On Saturday Abbas had asked that about 180 people be allowed out of Gaza after nine people were killed during the day in the deadliest internal fighting with Hamas since the Islamists seized power in June 2007.

It followed a July 21 bombing that killed five Hamas militants and a little girl, which the Islamists blamed on Fatah's Helis clan.

Abbas said meanwhile that Egypt plans to invite Palestinians for talks in Cairo.

'Dialogue is important. We have called for it. Egypt has agreed to invite Palestinian factions to meet in Cairo,' he was quoted in the statement as saying.

'We can't lose hope. We disagree and fight, but we have to work together to bridge the big gap created unfortunately by Hamas.'

Abbas urged the Islamists to 'resort to reason and logic and accept the law.'