Hundreds of police officers have surrounded a former school in Berlin which has been occupied by refugees who refuse to leave.

The predominantly African refugees are demanding the right to stay in Germany, even though most of their asylum applications have been rejected.

Adam, a Sudanese refugee who only gave his first name, told reporters on Friday that many of the migrants had climbed onto the roof and were ready to jump off the building if police entered it.

The tense stand-off involved 40 to 80 refugees and supporters who stayed in the building after police earlier this week evicted the majority of the roughly 200 who had occupied it since 2012.

City officials say they are willing to negotiate with the refugees about their demands but only if they leave the building.