HONG KONG (Reuters) - Dozens of Hong Kong pro-democracy activists will be sentenced later this week in a years-long subversion trial that has spotlighted what critics say are erosions to the city's freedoms under a China-imposed national security law.

A Hong Kong court will this week sentence 45 democratic campaigners in a major national security trial, with potentially heavy jail terms poised to further damage the financial hub's once lively pro-democracy movement,

Police have stepped up security since the weekend, ahead of final hearing in biggest prosecution under Beijing-decreed national security law.