i-Sharif, Afghanistan, Ramadan 18, 1431 / Aug. 28, 2010, SPA -- German Defence Minister Karl-Theodor zu Guttenberg and the speaker of the German parliament, Norbert Lammert, arrived Saturday in Afghanistan on a visit that was kept secret in advance for security reasons. Both were visiting German troops serving with the International Security Assistance Force (ISAF), beginning in Mazar-i-Sharif, according to dpa. It was Guttenberg's fifth trip to Afghanistan since he became defence minister last October. The mission is the German armed forces' biggest current deployment. Germany's parliament has authorized up to 5,350 personnel to serve in Afghanistan.