HONG KONG, Dec 30 (Reuters) - Two former senior editors of Hong Kong"s Stand News were charged with conspiring to publish seditious materials and denied bail by a court on Thursday, a day after a police raid on the pro-democracy media organization that prompted its closure. About 200 officers raided the online publication"s office, froze its assets and arrested seven current and former senior editors and former board members on Wednesday. Media advocacy groups and some Western governments criticised the raid and arrests as a sign of further erosion of press freedoms since China imposed a sweeping national security law in the former British colony last year. read more Magistrate Peter Law in the West Kowloon Magistrates" Court denied bail applications for former Stand News chief editor Chung Pui-kuen and acting chief editor Patrick Lam. Hong Kong laws restrict media coverage of bail hearings. Along with Best Pencil (Hong Kong) Limited, the corporate entity behind Stand News, the two men were charged with conspiring "to publish and/or reproduce seditious publications," according to the charge sheet. Four former members of the Stand News board - former democratic legislator and barrister Margaret Ng, pop star Denise Ho, Chow Tat-chi and Christine Fang - were released on police bail pending further investigations. They were not charged yet. Police said all four are due to report to police in late March. Ng told reporters as she left the police station that, "continuing to care for each other is very important". Ho, a Canadian citizen, left without comment. The seven people arrested on Wednesday also included Chung"s wife, Chan Pui-man. Formerly a senior editor with the pro-democracy Apple Daily newspaper, she was already being held in prison on different charges and was re-arrested there. Reuters could not reach Best Pencil or any of the seven arrested on Wednesday or their legal representatives for comment. Hong Kong returned to Chinese rule in 1997 with the promise that wide-ranging individual rights, including a free press, would be protected. But pro-democracy activists and rights groups say freedoms have been eroded, in particular since China imposed the new national security law after months of at times violent pro-democracy protests. U.S. Secretary of State Antony Blinken described Wednesday"s arrests as unjust and called on Hong Kong and Chinese authorities to "cease targeting Hong Kong"s free and independent media," saying it undermined the financial hub"s credibility. read more Hong Kong"s government denies targeting the media and curbing its freedoms. Hong Kong Chief Executive Carrie Lam, said the action against Stand News was aimed at seditious activity. "These actions have nothing to do with so-called suppression of press freedom," she told reporters. "Journalism is not seditious ... but seditious activities could not be condoned under the guise of news reporting." "BLACK SHEEP" Set up in 2014 as a non-profit organisation, Stand News was the most prominent remaining independent pro-democracy publication in Hong Kong after a national security investigation this year led to the closure of jailed tycoon Jimmy Lai"s Apple Daily newspaper. Stand News shut down hours after the raid and all of its employees were dismissed. Its website was not accessible on Thursday and its London bureau chief, Yeung Tin-shui, said on Facebook his office had also closed. Beijing"s main representative Liaison Office in Hong Kong, said Stand News was an "out-and-out political organisation" that "kept publishing articles that incited others to use violence and even split the country". The Chinese foreign ministry"s Hong Kong office said support for press freedom was being used as an excuse to disrupt stability in the city. "Those who engage in activities that endanger national security ... under the cover of journalism are the black sheep tarnishing the press freedom and will be held accountable," it said in a statement.