By Ali Sawafta
RAMALLAH, West Bank (Reuters) - A prisoner swap between rival Palestinian factions Fatah and Hamas could decide the fate of a summit in Cairo on Sunday to heal the split in Palestinian ranks.
Egypt hopes to win the agreement of both factions on a coalition government ahead of elections in the Gaza Strip and the West Bank to reform security services and forge a political partnership that could boost peace moves with Israel.
But a senior Hamas leader in the West Bank, Raafat Nassif, said the Cairo reconciliation summit -- key to creating a solid foundation for wider peace talks -- would not go ahead unless "all political prisoners" were released by Fatah.
On Tuesday, there were conflicting reports on whether the release of detainees was going ahead.
Officials of the Fatah movement of Western-backed Palestinian President Mahmoud Abbas said 21 jailed supporters of the Islamist group Hamas had already been set free.
"There was an agreement to resolve many sticking points and yesterday 21 people were released in the West Bank," Fatah official Mahmoud al-Aloul said.
"There will be other steps to follow here and in Gaza," he added, meaning Hamas would now free Fatah members it holds.
A Hamas official in the Israeli-occupied West Bank denied any members of the Islamist movement had been released.
Fatah holds sway only in the West Bank after losing control of the Gaza Strip to Hamas in internal fighting in 2007.
Mahmoud Mesleh, a Hamas lawmaker in Ramallah, told Reuters the group was still waiting for Fatah to make good on promises to free its men.
"They spoke about stopping detentions. But some people were arrested yesterday, and some were arrested today," Mesleh said.
"We still hope prisoners can be freed in the coming days, we have not lost hope yet."
Hamas says at least 500 are held in Palestinian prisons in the West Bank. Fatah has not said how many of its people are held by Hamas in the Gaza Strip.
Each faction accuses the other of subjecting some prisoners to torture and summary execution, but both deny they detain anyone for political reasons.
Fatah hopes to establish a Palestinian state in the West Bank and Gaza Strip in land-for-peace talks with Israel. Hamas, considered a terrorist group by Israel and the West, does not recognise Israel and will only consider a long-term cease-fire.
Peace talks following Israel's devastating 22-day war on Hamas in its Gaza Strip stronghold are now being conducted on at least three planes.
The Palestinians are seeking ways to end their split; Israel and Hamas are looking for accord on a durable cease-fire in Gaza; Israel's outgoing government is suggesting a prisoner exchange with Hamas to free an Israel soldier seized three years ago.
The jigsaw puzzle is further complicated by a power struggle in Israel after last week's inconclusive election which gave the right-wing bloc the most seats but put the centrist party first.
U.S. President Barack Obama's Middle East peace envoy Senator George Mitchell is due back in the region next week, but talks on a comprehensive peace are unlikely to be resuscitated until there is one clear interlocutor on each side.
(Additional reporting by Nidal al-Mughrabi; writing by Douglas Hamilton; editing by Alison Williams)