KABUL - Afghan election authorities have agreed to push back a parliamentary election to September from May, pleasing diplomats who wanted time to prevent a repeat of the rampant fraud that plagued a presidential vote last year.

The announcement on Sunday eases one of the main sources of friction between President Hamid Karzai and his Western backers, days before a major conference in London aimed at plotting a course for Western countries to begin withdrawing their troops.

A draft agreement for that meeting anticipates a handover under which Afghan troops could be managing security in some provinces by early 2011, with foreign forces in a supporting role, a copy obtained by Reuters showed.

After a difficult 2009, the eight-year-old war's deadliest year, U.S. President Barack Obama and other Western leaders are anxious to repair their increasingly fraught relationship with Karzai and boost his government so it can look after itself.

Last month, Obama committed 30,000 more U.S. troops to Afghanistan, but also announced a target to begin withdrawing them by mid-2011 after building up Afghan security forces and government institutions.

Asked to comment on the draft communique for the Thursday London conference, British Defense Secretary Bob Ainsworth said the transition would be a long process. We'll be able to hand over parts of Afghanistan long before we hand over other parts.

The communique also commits Afghanistan to establish -- and the West to fund -- a program to reach out to insurgents and pay fighters to lay down arms. That received public support on Sunday from the conference's British hosts.

When people say to me, 'Should the Afghan government be talking to the Taliban?', I have a very simple answer, 'Yes, they should', Foreign Secretary David Miliband told BBC television.

It is very important that the political system is open enough to bring those insurgents who are willing to work within the Afghan constitution.

Donors will also promise to deliver more of their aid through the Afghan government, a practice Kabul says would improve its ability to manage its own affairs after years of contracts going to development agencies and Western firms.

ELECTION LOOMS

The conference will be Karzai's first appearance on the Western stage after his tainted re-election, and both sides hope to use the meeting to relaunch an image that was dented in countries with 110,000 troops in Afghanistan.

Clouding efforts to rehabilitate Karzai in 2010 is the prospect of another botched election. The parliament is one of the only Afghan institutions not appointed by the president and a rare outlet for peaceful opposition.

The presidential vote -- in which a U.N.-backed probe discarded as fraudulent nearly a third of votes cast for Karzai -- sparked a crisis of confidence in the West, and made Obama's plan to send more troops a much harder sell.

Since that election, diplomats have been working behind the scenes to persuade Karzai to postpone the parliamentary vote, originally scheduled for May 22, so that changes can be made to ensure there is no repeat of the fraud.

An international diplomat, speaking on condition of anonymity, called the postponement a pragmatic and sensible decision which will allow time for reform of the key electoral institutions to enable cleaner parliamentary elections.

The new date of September 18 also means the vote will fall after the traditional summer fighting season, giving more time for the expanding international military force to help improve security, especially in the Taliban's southern heartland.

Last year, Taliban threats kept voters away from the polls in much of the south. With few genuine votes cast there, otherwise empty ballot boxes ended up stuffed with fake ones.

The United Nations is holding tens of millions of dollars for Afghan elections in an account, but diplomats say the money will not be released unless the electoral process is improved.

Critics want Karzai to replace some election commission members who they say unfairly backed him and waved through fraud.

Western leaders also want Karzai to do more to fight corruption, which they say fuels support for the Taliban. A U.N. report last week found that nearly a quarter of Afghanistan's gross domestic product (GDP) is spent on bribes.

The language in the draft communique suggests that corruption will not take center stage in London.

It lists a number of anti-corruption measures, but describes them either as steps Karzai has already announced or measures to be discussed at a future conference, not new undertakings to be agreed in London.

(Additional reporting by David Milliken in London; writing by Peter Graff; Editing by Noah Barkin)