New Delhi, Feb 23 : Chinese police have detained at least five activists who supported the recent mass protests in two major cities against the slashing of retirees medical insurance benefits earlier this month, a media report said. Among those detained was veteran rights activist Zhang Hai, who was picked up by authorities in the southern city of Shenzhen, a resident of Wuhan, who gave only the surname Zhang, said, Radio Free Asia reported. "One of the five persons detained in connection with the silver protests was Zhang Hai ?? I heard he was detained in Shenzhen," the woman said, adding, "There was also a 23-year-old man who was detained for singing 'The Internationale' with some older people." The detentions come after thousands of people took to the streets of two Chinese cities ?? Wuhan and Dalian ?? on February 15 in a second mass protest over major cuts to their medical benefits, RFA reported. Protesters were shown in social media video clips singing the Communist anthem 'The Internationale' as well as China's national anthem. "There was also a taxi driver called Shu Li, who was detained around February 20," Zhang said, adding, "He was detained for going to support ." Shu was handed a 10-day administrative jail sentence, which can be handed out for up to 15 days to people the police see as troublemakers. However, many detainees aren't released but held under criminal charges when the administrative sentence is complete, RFA reported. /IANS