Britain's Labour party will announce its new leader June 24 at a conference in northern England to replace Prime Minister Tony Blair, it said Sunday.

Blair will formally step down as prime minister June 27, handing power to his replacement — almost certain to be Treasury chief Gordon Brown.

But Brown acknowledged at a campaign event Sunday that the unpopular Iraq war had cost his party support and threatened to hamper his own prospects of winning the next national election, expected in 2009 or 2010.

"We have a divided country over Iraq, there's no doubt about that," Brown told an audience in the southern England seaside resort of Brighton.

The prospective leader said British troop levels would continue to fall. "There will be less troops in Iraq next month and the month after," he said.

Nominations of candidates to replace Blair — and his deputy John Prescott — will open Monday, when lawmakers with the backing of 44 fellow Labour lawmakers can put themselves forward.

Two leftist lawmakers are hoping to run against Brown for the Labour leadership and force the party to hold a ballot, but neither man has yet secured the necessary backing.

Six senior lawmakers have said they will compete to replace Prescott, who announced he would also relinquish his position June 27.

Blair will be replaced as Labour leader June 24, but remain as prime minister for three days — before formally presenting his resignation to Queen Elizabeth II at Buckingham Palace.

"This will be the first time in our history that the party as a whole is electing not only a new leadership team but also a party leader who will become prime minister," said Labour lawmaker Jacqui Smith, the party's chief whip.

Nominations for both posts will close Thursday and candidates will take part in a campaign tour across England, Scotland and Wales, making a series of speeches and taking part in debates, Labour said in a statement.

The party will hold a conference in Manchester on June 24 to announce the results of postal ballots. Around 3.2 million party members, Labour lawmakers and member of affiliated labor unions will vote. If Brown has no challenger, members will vote only for a deputy.

Brown, who was interviewed by film director Anthony Minghella at the Brighton rally, said that as British leader he would continue Blair's attempts to push for a permanent settlement to the Israeli-Palestinian conflict.

"In Northern Ireland, people realized they could have prosperity and peace and that a return to violence means a loss of peace and a loss of prosperity, we have got to build a peace to give prosperity to Palestinians," he said.

The Treasury chief said he also believed that multilateral nuclear disarmament could be possible in the future.

Brown has also pledged to help young Britons priced out of the housing market to purchase homes and said his vision was of a "home-owning, asset-owning, wealth-owning democracy."

Blair has given Brown his endorsement as his successor, saying he had the "strength, judgment and experience" to be British leader.