Two people were killed and 20 injured when security opened fire on protesters in the city of Taiz in southern Yemen on Friday.
"Many injured are besieged inside the mosque, and security prevented doctors from helping them," a doctor and activist who has been involved in protests for months told the German Press Agency dpa.
"Taiz has turned into a city of ghosts and war," he said in a telephone interview, in which gunshots could be heard in the background.
He said that both police and army forces have surrounded the city, and were preventing people from leaving or entering.