US Vice President Joe Biden said Tuesday that the United States will not withdraw its troops from Afghanistan completely in 2014 if Afghans did not want his country to do so.

About 97,000 American troops in Afghanistan are expected to start limited withdrawals in July ahead of the scheduled transfer of responsibility for security to Afghan forces in 2014.

But Biden, on the second day of his visit to war-torn Afghanistan, said: "We're not leaving if you (Afghans) don't want us to leave."

Speaking after talks with Afghan President Hamid Karzai in Kabul, he added: "It's not our intention to govern or to nation-build -- as President Karzai often points out, this is the responsibility of the Afghan people...

"We stand ready to help you in that effort and we'll continue to stand ready to help you in that effort after 2014."

Karzai said he and Biden had held one-to-one talks that lasted one hour and 45 minutes.

"We discussed the transition process in 2014 and how best to proceed with it. We had a good discussion, it made me happy," Karzai told the same press conference, which came a day after Biden's surprise arrival in Afghanistan.

Shortly after arriving in Kabul, Biden spent nearly two hours with the commander of international troops in Afghanistan, US General David Petraeus, and US ambassador Karl Eikenberry.

Aides travelling with the vice president said his trip came at a "pivot point" for the US in Afghanistan, adding it would allow Biden to review progress towards handing responsibility for security to Afghan forces by 2014.

In 2010 coalition troops, which in total number about 140,000 troops, suffered their bloodiest year yet in Afghanistan, with 711 deaths, according to the website.