GENEVA, Nov. 21 (Xinhua) -- Switzerland announced on Wednesday that it would end its four years' cooperation with the NATO-led international forces in Afghanistan by recalling its military personnel.

    Two Swiss army officers, currently working with a German team in the northeastern Kunduz province, will return home by March next year, Swiss Defense Minister Samuel Schmid told a press conference in Bern, the Swissinfo website reported.

    Schmid said he took the decision for security reasons. The NATO-led mission in Afghanistan has become a peace enforcement operation rather than a peacekeeping duty, he said.

    According to Schmid, a continued Swiss military presence in Afghanistan - although "rather symbolic" - is impossible because it goes against the spirit of the constitution and is not in line with the law.

    The Swiss decision comes a few weeks after a meeting of NATO defense ministers to boost efforts to provide security in Afghanistan.

    Switzerland, which is not a member of NATO but joined its Partnership for Peace program, has participated in the NATO-led mission in Afghanistan since 2003.

    According to the Swiss Defense Ministry, the nature of NATO's engagement in Afghanistan has changed since 2005. But its mission has progressively turned into a campaign against insurgents.

    Even in the regions where warlords and fighters only carry out sporadic activity, the mission has faced difficulties because of the need for troops to resort to self-protection measures.

    In areas of the country where the Taliban have regained strength, reconstruction work has become practically impossible, the Swiss authorities said.