NATO Secretary-General Jens Stoltenberg is in Kabul for an unannounced trip to visit troops and meet Afghanistan's new leadership.
Stoltenberg was to meet with President Ashraf Ghani before a joint press conference with the Afghan leader on November 6.
Stoltenberg, who took over as the head of NATO alliance on October 1, visited a training center for Afghan special forces shortly after his arrival.
He told them NATO will continue its support after the alliance's combat troops withdraw from the country at the end of 2014.
Foreign troop numbers in Afghanistan peaked at 130,000 in 2010, but are now below 34,000.
A residual force of up to 12,000 U.S. and NATO troops will remain beyond 2014 to provide training and support.
Afghanistan now has a total of about 350,000 security forces – including members of the Afghan National Army and the Afghan National Police.