Stockholm - Swedish Prime Minister Fredrik Reinfeldt arrived Monday on an unannounced visit to Swedish troops based in Afghanistan, news reports said.

Sweden is this year to raise its some 400-strong force in northern Afghanistan to around 500.

Along with forces from neighbouring Finland, the Swedish forces are based in Mazar-e-Sharif in northern Afghanistan as part of the NATO-led International Security Assistance Force (ISAF).

After several blasts aimed at Swedish forces on patrol, the Swedish Defence Ministry recently decided to deploy three heavier Combat Vehicle 90 units and 12 light armoured vehicles in Afghanistan.

Foreign Minister Carl Bildt last year attended the opening of the Swedish embassy in Kabul where diplomatic presence is expected to help improve monitoring and dialogue. (dpa)