US Defense Secretary Robert Gates flew into Kabul on Saturday for a farewell visit to Afghanistan after four and a half years heading up the war effort at the Pentagon.

Gates is expected to visit some of the roughly 90,000 US troops serving in Afghanistan as part of a 130,000-strong US-led international force trying to stabilise the country and reverse a bloody Taliban insurgency.

The visit, his 12th as Pentagon chief, comes with the United States expected to start troop withdrawals in July and as the White House debates the scale and pace of the drawdown, a decade into the increasingly unpopular war.

US President Barack Obama says some troops will go home in July but has yet to reveal how many. All foreign combat troops are due to leave by 2014.

Gates told reporters en route to the Afghan capital, however, that the amount of money the United States spends on the war -- roughly $120 billion a year -- should not shape the decision on the speed of the withdrawals.

Some US officials and lawmakers say this should be a key factor amid a fragile domestic economy. Pressure for a swifter drawdown has also grown since US Navy SEALs killed Al-Qaeda founder Osama bin Laden in Pakistan last month.

"I think that once you've committed, that success of the mission should override everything else. Because the most costly thing of all would be to fail," Gates said.

"Now that does not preclude adjustments in the mission or in the strategy. But ultimately the objective has to be success in the mission that's been set forth by the president."

The killing of the Al-Qaeda leader last month has fuelled calls for a reassessment of the war effort.

US troops led the 2001 invasion of Afghanistan after the then Taliban regime refused to hand over bin Laden in the wake of the September 11, 2001 attacks blamed on Al-Qaeda.

There are now signs that US officials are increasingly hoping for a negotiated settlement to the conflict.

In Singapore on Saturday, Gates said military pressure on the Taliban could lead to "real opportunities" for peace talks with Afghan insurgent leaders during the next year.

On the plane from Singapore to Kabul, Gates said the decision on the drawdown would have to include a longer-term blueprint on force levels.

Obama has "made a commitment that we will begin this process next month", Gates said.

"But obviously as we look ahead, we're going to have to think about sort of the next year or two in terms of where we are."

He said the drawdown decision would have to take into account the possible effect on allies and declining public support for the war.

"We have to weigh the impact potentially on our allies of what we decide. "We certainly don't want to precipitate a rush for the exits by our partners," he said.

"By the same token, you can't be oblivious to the growing war weariness at home and the diminishing support in the Congress."

Gates also admitted to a certain amount of trepidation at the prospect of bidding farewell to US troops after so long in the job.

"This is principally an opportunity for me to thank the troops. And bid them farewell," he said, his voice breaking as he paused to hold back tears. "So I don't expect it to be very easy."

Tweet

Related Links News From Across The Stans