* Political crisis dashes hope of new president taking part
* Karzai will not attend summit, spokesman says
* Afghan deadlock creates doubt over future NATO mission
By Adrian Croft
BRUSSELS, Sept 1 (Reuters) - Afghanistan is expected to send its defence minister to a NATO summit in Wales this week, NATO officials said on Monday, after a political crisis dashed hopes that a newly-elected president could make his debut on the international stage there.
Who, if anyone, would represent Afghanistan at a summit that will discuss the country's future had become a guessing game following the country's disputed presidential election.
The summit on Thursday and Friday will mark the end of 13 years of combat in Afghanistan by U.S. and other foreign troops.
The summit will open with a session on Afghanistan at which U.S. President Barack Obama and other NATO leaders will be joined by officials from 27 other countries as well as representatives from the United Nations and European Union.
NATO Secretary-General Anders Fogh Rasmussen said last month that a new Afghan president would attend the summit if he took office in time.
But that now appears impossible after it emerged on Monday that talks on a power-sharing deal between Afghanistan's rival presidential candidates had collapsed.
"It has become clear that the electoral process in Afghanistan is very unlikely to reach its conclusion in time for a new Afghan president or president-elect to join us in Wales," said a senior NATO official briefing reporters on condition of anonymity.
"We understand President (Hamid) Karzai has nominated Defence Minister Bismullah Khan Muhammadi to represent the Afghan government in Wales," the official said.
Rival candidates Abdullah Abdullah and Ashraf Ghani have both claimed victory in a vote intended to mark the country's first democratic transfer of power.
Abdullah's team has pulled its observers from the U.N.-led audit of votes from the June 14 run-off ballot, saying it was dissatisfied with the way that fraudulent votes were being handled.
The setbacks have deepened the uncertainty about when Karzai can hand over power to a successor.
Karzai will not attend the NATO summit because of his disagreements with Washington over Afghan security needs after most foreign troops leave his country at the end of 2014, his spokesman said last week.
The political uncertainty calls into question whether NATO will be able to go ahead with its plans to keep a smaller training and advisory mission in Afghanistan after the end of this year.
U.S. and NATO officials say foreign troops cannot stay unless the Afghan government signs two agreements providing a legal basis for them to do so.
Karzai has refused to sign. Both presidential candidates say they would sign but if the election deadlock drags on much longer, NATO officials say they may be forced to take a decision to pull out NATO troops altogether at year-end. (Editing by G Crosse)