Hong Kong’s pro-democracy newspaper Apple Daily could be forced to shut down in a "matter of days" as the authorities have frozen its bank account, said an adviser of the paper's jailed founder Jimmy Lai. 

Mark Simon told the BBC that the newspaper could "do nothing while none of its bank accounts are functioning". Apple Daily, a tabloid with a wide circulation, carries news critical of Hong Kong and mainland Chinese leadership.

BBC report:  Apple Daily: HK pro-democracy paper could 'shut within days', says adviser

"If you don't have money you can't order services. Most importantly, you can't promise to pay people when you don't have access to the cash to cover those expenses. That's illegal in Hong Kong," said Simon.

"The paper is still on the newsstands today but it is only a matter of days before it won't be there unless its bank accounts are unfrozen." 

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The paper's publisher, Next Digital, is holding a board meeting on Monday to discuss the future of the top-selling newspaper that was started 26 years ago.

The closure of Apple Daily would bring to an end the former British colony's reputation as an open and free society and send a warning to other media houses to toe the government line.

"Vendors tried to put money into our accounts and were rejected," Simon told Reuters by phone from the United States. "We thought we'd be able to make it to the end of the month. It's just getting harder and harder. It's essentially a matter of days."

Chief Editor Ryan Law, 47, and Chief Executive Cheung Kim-hung, 59, were denied bail on Saturday after being charged with collusion with a foreign country. 

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Three other executives were also arrested on Thursday when 500 police officers raided the newspaper's offices, drawing condemnation from Western nations, global rights groups and the U.N. spokesperson for human rights.

Last Thursday, some 500 police officers raided the offices of Apple Daily in Hong Kong, saying its reports had breached the national security law.

Police also arrested the editor-in-chief and four other executives at their homes and froze HK$18m ($2.3m; £1.64m) of assets owned by three companies linked to Apple Daily – Apple Daily Limited, Apple Daily Printing Limited and AD internet Limited.

Photos published online by Apple Daily showed police going through reporters' computers.

In a statement, police said their warrant "covered the power of searching and seizure of journalistic materials".

In a press briefing later that day, police said that Apple Daily had published more than 30 articles calling on countries to impose sanctions on Hong Kong and mainland China since 2019.

Jimmy Lai, the paper's founder, is currently in jail for a series of charges, including participating in an unauthorised assembly in 2019.