The trio were part of a group of seven facing terrorism charges related to a homemade bomb that went off in a hospital toilet in January 2020, and explosive devices found at a railway station the following month.

They were in a group on the Telegram messaging app calling itself "92 sign", which claimed credit for the two incidents that resulted in no casualties.

On Thursday all seven were acquitted of terrorism, but three were convicted of an alternative charge related to conspiracy to cause an explosion, according to the South China Morning Post.

Lukas Ho, Lee Ka-pan and Cheung Ka-Chun face up to 20 years behind bars.

Lawyers will make arguments on sentencing next month.

The group was also linked to a third bomb plot which would have amounted to an "indiscriminate attack" had it not been foiled by police, prosecutors said earlier.

It is only the second time a case has been tried under Hong Kong's 2002 anti-terrorism law, which was enacted following a United Nations Security Council resolution to fight international terrorism.

The first criminal trial involving the law ended last year with multiple defendants jailed, one of whom was sentenced to nearly 24 years in prison.