The US has urged Beijing to release the dissidents rounded up in Hangzhou.
Five out of nine activists had already been freed, according to a Hong Kong human rights group. Cheng Fan, the last dissident freed, was escorted to his Wenzhou home on Monday by police from the Zhejiang capital.
The US Embassy in Beijing sought urgent information about 1989 activist Wang Youcai, among others, and called for their release, said State Department spokesman James Rubin.
But Beijing responded by saying most of the dissidents were 'criminals' and hit out at what it called US meddling.
Washington played down suggestions the roundup was a snub to US President Bill Clinton so soon after he praised Beijing's increasing openness.
Mr Rubin said the embassy was 'following up on these cases, requesting information from the relevant authorities and urging the release of those who reportedly remain detained'.
'The President made clear during the summit that promoting respect for human rights is a top priority . . . He made those views well known.' White House spokesman Mike McCurry also criticised the arrests.