The All About Macau Media (AAMacau) news platform, co-founded by late journalist Ng Sio Ngai more than a decade ago, has often been critical of social issues in the Chinese city.

AAMacau, whose Chinese-language name means "discuss as much as possible", runs digital and print platforms and also has a social media presence.

The outlet said this month's print edition would be its last, with the rest of its operation to end in December.

It said it had been told by Macau officials that it "no longer meets the statutory requirements to engage in relevant activities" under the Chinese special administrative region's media law and that its monthly publication registration number has been revoked.

"Facing resource constraints, mounting external pressures, and the need for our reporters to navigate judicial proceedings, the team found it increasingly difficult to maintain reporting standards," AAMacau said.

It said it "had no choice but to make this difficult decision".

In April, two AAMacau reporters were detained by police while covering an event in the city's legislature, which it said was the first case of its kind in Macau.

It said on Thursday that three of its journalists could face criminal charges over the incident.

The city's Government Information Bureau has not yet responded to an AFP request for comment.

- 'Swift deterioration' -

Macau, which has its own legal system largely based on Portuguese law, enacted national security legislation in 2009 and widened its powers in 2023.

The Committee to Protect Journalists said the closure of AAMacau is "a blow to press freedom and a highly troubling development".

It "marks a swift deterioration" in Macau's media environment, the advocacy group told AFP.

Began as a weekly feature in a local newspaper in 2010, AAMacau established its website about two years later, followed by the first monthly magazine printed in May 2013.

In recent years, the outlet has transitioned into a subscription and donation-based funding model.

AAMacau said its decision came about a year after it started facing restrictions in accessing government events.

Political scientist and veteran journalist Eric Sautede called the outlet's closure an "absolute loss".

He said AAMacau had "helped foster a measure of accountability among those in power -- both in government and in the private sector".