NATO Secretary General Anders Fogh Rasmussen made a surprise visit to Kabul and told a news conference on Wednesday that NATO forces would remain in Afghanistan for "as long as it takes."

During the joint press conference with Afghan President Hamid Karzai, Rasmussen said there were more than 40 nations in Afghanistan, adding that there is not yet a military solution to the problems in the country and that a "comprehensive approach" was needed along with a stronger international commitment.

The 56-year-old former Danish prime minister was sworn into office on Saturday. He replaced Dutchman Jaap de Hoop Scheffer, who spent five years in office.