Established in 1958, the Hong Kong Federation of Students (HKFS) played a leading role in mobilising the Chinese city's student community to participate in once-vibrant social movements.

"As circumstances have changed, HKFS members and their allies have faced increasingly severe pressures in recent years. After careful consideration of all factors, HKFS has decided to draw a full stop today," the group said in a statement.

"We have never been absent from major political and social events throughout the years," HKFS said, mentioning the organisation's role in championing social causes and fighting for reform over nearly seven decades.

The decision was "very difficult and painful", Isaac Lai, chair of the HKFS representative council, told AFP.

"Our members have all faced increasing risks or pressures. We made this decision under a circumstance of no alternative, with no other choice," Lai said.

Several HKFS members have received threatening letters or been stalked, he added.

In its early years, the HKFS was a pro-Beijing student group, but it shifted its stance in the 1980s to support pro-democracy movements in Hong Kong and mainland China.

It was a founding member of the alliance that organised a vigil to mark Beijing's deadly crackdown on demonstrators in Tiananmen Square in 1989 -- but those events have been banned since 2020.

After the 1997 handover of Hong Kong to China, HKFS has been a key force in pro-democracy social movements.

In 2014, HKFS initiated a class boycott campaign, which sparked the Occupy Central movement where hundreds of thousands of Hong Kongers staged a 79-day sit-in around the city's Central business district, calling for universal suffrage.

On Thursday, an AFP reporter saw the federation's signboard had been removed at its address.

- 'Steadily shrinking space' -

Student unions at Hong Kong universities were once hotbeds of political activism and played a role in the city's huge and sometimes violent pro-democracy protests in 2019.

They either shrank their operations or were shut down entirely after Beijing imposed a national security law in Hong Kong a year later, which critics say has curbed dissent.

In December, a student union from Hong Kong Baptist University was ordered to suspend after a condolences message was posted on campus wall following a fire that killed 168 people.

Multiple college unions have also announced their dissolution in recent months, citing reasons including institutions' refusal to recognise their status.

"These developments reflect the sustained and systematic pressure faced by student organisations, steadily shrinking their space to operate," Hong Kong Centre for Human Rights said in a statement.

Lai said that student participation in Hong Kong's civic society through institutional and organisational channels has become "extremely difficult", but they will insist on speaking out for social injustice.

"We must all still cherish the power of the individual," he said.