Police in Hong Kong have detained pro-democracy activists on the anniversary of the Tiananmen Square massacre.

Authorities have banned public commemoration of the 1989 incident, which saw China crush peaceful protests in Beijing with tanks and troops.

However, dozens of candlelight vigils are expected to take place in cities around the world.

Among those detained was 67-year-old campaigner Alexandra Wong, widely known as "Grandma Wong".

Amid a tense evening in Hong Kong, she was detained while carrying flowers near Victoria Park, where vigils had been held for decades.

The leader of one of Hong Kong's main opposition parties has also been detained and placed in a police van. Chan Po Ying, a veteran pro-democracy activist who heads the League of Social Democrats party, was holding an LED candle and two flowers.

Events to mark the 1989 massacre in Beijing are banned in mainland China.

Hong Kong was previously the only Chinese city where these commemorations were allowed, under the city's semi-autonomous economic, political and legal set up - known as "one country, two systems" - established when the city handed over to China by the UK in 1997.

But public events to mark the anniversary have since been outlawed, after the Chinese government imposed astrict national security law outlawing many forms of dissentin 2020.

The annual commemorations have not been held since 2019, after being initially banned under Hong Kong's Covid regulations.

This year, a pro-Beijing carnival is being held in Victoria Park instead.

Nearby Victoria Park has hosted annual candlelit vigils to mark Tiananmen Square since 1990, often drawing tens of thousands of people to mark the day, known as June Fourth in much of China.