(For more on Afghanistan, click on [ID:nAFPAK])

* Afghanistan prepares for Nov. 7 second round

* Karzai says accepted run-off the sake of stability

* Campaigning expected to kick off on Saturday

* UN says some election fraud is unavoidable (Adds excerpts from CNN interview with Karzai for Sunday in which vows inclusive govt, paragraphs 20-21)

By Maria Golovnina

KABUL, Oct 23 (Reuters) - Afghanistan's Hamid Karzai said he wanted a better and cleaner presidential election run-off in November to bring stability at a time when Taliban violence is at its worst in eight years of war.

Karzai agreed to face his main rival, Abdullah Abdullah, in a Nov. 7 run-off after a U.N.-led fraud inquiry annulled enough of his votes from the first round in August to trigger a rematch.

The Afghan leader has played down fraud allegations but bowed to international pressure and ordered a run-off as a way to bolster the election's credibility at a time when Washington is weighing whether to send more troops to Afghanistan.

In a statement late on Thursday, Karzai said he accepted the run-off for the sake of stability.

"I accepted the second round in the interests of the nation, to strengthen stability and prospects for democracy in Afghanistan," the presidential palace quoted him as saying.

"Now that we are holding the second round in two weeks, I want it to be better than the first round."

Concerns about security and a repeat of the fraud that tainted the first round have cast a shadow as officials in Afghanistan kicked off hasty preparations for the vote.

The U.N. special envoy to Kabul said some level of fraud was inevitable and vowed to do more this time to prevent it.

"I do not expect I will be able to eliminate fraud in two weeks' time. I think that is beyond the realm of what is possible in such a short time," Kai Eide said during a NATO meeting of defense ministers in Bratislava. [ID:nLN265452]

"But I what I do expect, and what we will try to do, is to reduce the level of fraud."

A top Afghan election official has already warned that domestic and international forces will hardly have enough time to provide full security ahead of the vote. [ID:nSP484242]

U.S. AND NATO STRATEGY

Washington is watching the election closely because it forms a key element of Western efforts to stabilize Afghanistan, a rugged nation of 33 million where militants involved in Sept. 11, 2001 attacks are believed to have once sought sanctuary.

President Barack Obama is considering a call by his Afghanistan commander General Stanley McChrystal for tens of thousands more soldiers. Obama said this week he could reach a decision before the outcome of the Nov. 7 vote.

Also in Bratislava, NATO Secretary-General Anders Fogh Rasmussen urged member states to support McChrystal's plan for combating the worsening insurgency. [ID:nLN448659]

"I firmly believe that if we show people in our countries that we are making progress, that there is light at the end of the tunnel, they will support us as long as it takes," he said.

McChrystal briefed the defense ministers in Bratislava on his recommendations more foreign troops be deployed and to boost the size of the Afghan army and police to 400,000 from around 230,000 now so they can take over responsibility for Afghanistan's security. [ID:nLN331800]

The ministers voiced support for more Afghan troops training but they side-stepped the issue of any increase in foreign troops.

Karzai is widely expected to win the second round largely due to his strong support base among fellow Pashtuns -- Afghanistan's largest ethnic group. He remains popular with many Afghans who see him as an experienced leader.

Former foreign minister Abdullah, on the other hand, is half Tajik and half Pashtun and is sometimes seen as a unifying candidate who can cross divisive ethnic lines in Afghanistan.

Karzai also promised that he will have an inclusive government if he wins the second round though he did not offer details on how he might do that. [ID:nN23495620]

"If (Abdullah) wants to come and work in my government, he is most welcome. I'm known for consensus and building it and for inclusivity, and that's a good trademark," he told CNN in an interview to be broadcast on Sunday.

In Washington, U.S. envoy to Pakistan and Afghanistan Richard Holbrooke dismissed reports he had strained ties with Karzai, saying their relationship was "fine", and he looked forward to working with the Afghan president if he won the second round of voting. [ID:nN23118340]

Re-running the vote poses a big logistical challenge, particularly as the rapid onset of winter makes many parts of the country inaccessible.

Election officials have to rely on U.N. planes, trucks and donkeys to deliver ballots to far-flung locations. Official campaigning is expected to kick off at noon on Saturday.

To prevent a repeat of fraud, many district election officials would be replaced, officials said. (Additional reporting by Hamid Shalizi, David Brunnstrom and Phil Stewart in BRATISLAVA; Writing by Maria Golovnina; Editing by Ron Popeski and Philip Barbara) (For more Reuters coverage of Afghanistan and Pakistan, see: http://www.reuters.com/news/globalcoverage/afghanistanpakistan)

AlertNet news is provided by