“We Germans are of course worried about our representatives in the affected countries,” Foreign Minister Guido Westerwelle said on broadcaster ARD’s Morgenmagazin programme.
He added that not only had security measures been bolstered at embassies and consulates in Islamic countries, but soldiers stationed in Afghanistan had also been ordered to be more alert.
What exactly had been done to improve security remains a secret though, the ministry said. They confirmed that, at this point, they knew of no protest action aimed at German outposts.
The heightened measures came after the US ambassador to Libya was killed and three others injured when the consulate was attacked in the city of Benghazi Tuesday.
A further four people were killed at the US embassy in Yemen on Thursday, after similar attacks, while some 220 people were injured in anti-US protests in Cairo.
The protests began after the video - an amateurish film denigrating the Prophet Mohammed allegedly linked to evangelical and Coptic Christians in the United States - was released.
Demonstrations have spread across the Middle East, and to Bangladesh, Iran, Iraq, Israel and the Gaza Strip, Kuwait, Sudan and Tunisia.
The White House said security had been tightened at US diplomatic missions around the globe.
Der Spiegel also reported that other German institutions and aid organisation offices had been advised to do more to protect their staff.
Westerwelle called for calm in a speech in Berlin. "We share the condemnation and criticism of the video and its intention to provoke religious feelings, but that can never be an excuse for violence and murder," he said.