Thomas de Maiziere arrived in Afghanistan in an unannounced visit on Wednesday to meet with the German forces in northern Mazar-e-Sharif city of Afghanistan.
De Maiziere urged the government of Afghanistan not to wait until elections earlier next year, to sign the bilateral security agreement with Washington.
He also said that delaying the security pact with Washington will not be in the interest of Afghanistan, and warned that more pressure from Washington on president Karzai will not help to accelerate in finalizing the deal.
Germany has deployed around 3,400 troops under the NATO-led International Security Assistance Force (ISAF) mission in Afghanistan, which are mainly based in northern Afghanistan.
His trip to Afghanistan comes as a suicide bomber targeted a convoy of the German forces in near Kabul International Airport early Wednesday morning.
Taliban group spokesman, Zabiullah Mujahid claimed the responsibility behind the incident and said that the attack left 10 German troops dead.
However, security officials in Kabul deny the claims by the Taliban group spokesman and said no casualties were reported in the attack.