LONDON (Reuters) - The United States and Israel must change policy toward Hamas and engage the Palestinian militant group if progress is to be made on peace in the Middle East, a group of former peace negotiators said on Thursday.

Writing in Britain’s Times newspaper, 14 former foreign ministers and peace negotiators said the three-year policy under which Hamas has been ostracized by the international community had backfired and needed to be changed.

“There can be no meaningful peace process that involves negotiating with the representatives of one part of the Palestinians while simultaneously trying to destroy the other,” wrote the signatories, who include Britain’s Paddy Ashdown, a former negotiator in Bosnia, and Michael Ancram, who helped broker peace with the IRA in Northern Ireland.

Hamas, a militant group whose founding charter calls for Israel’s destruction, won a Palestinian parliamentary election in January 2006, defeating long-time rival Fatah.

But the group was immediately cut off by Israel, the United States and the European Union, which regard it as a terrorist organization. Peace negotiations have, however, continued with Palestinian President Mahmoud Abbas, who heads Fatah.

The letter’s signatories said Israel’s recent war against Hamas in Gaza had “demonstrated that the policy of isolating Hamas cannot bring about stability.”

“Bringing Hamas into the process does not amount to condoning terrorism or attacks on civilians,” the letter will say, according to excerpts provided in advance.

“It can strengthen pragmatic elements and their ability to strike the hard compromises needed for peace.”

The letter is published ahead of a visit to the region by George Mitchell, the newly appointed U.S. envoy to the Middle East, and Javier Solana, the European Union’s envoy.

On Wednesday, British Foreign Secretary David Miliband said that talking to Hamas was the “right thing to do” but Egypt and other parties were best placed to do so.

Israel has said that it will not deal with Hamas until it ends all violence, abides by already existing peace agreements and recognises Israel’s right to exist.