A Japanese freelance journalist known for his coverage of Hong Kong's 2019 pro-democracy protests said Friday he was sent back to Japan by the territory's authorities after being denied entry into the city.

Yoshiaki Ogawa, 54, arrived at Hong Kong's international airport on Thursday evening but was detained by officials and interviewed for around an hour about the purpose of his visit before being denied entry. He was sent on a return flight to Japan the next morning.

The journalist told Kyodo News he intended to be in the former British colony for the 26th anniversary of Hong Kong's handover to China on Saturday, adding that he was not given a clear reason for being denied entry.

Ogawa also said he thought his previous coverage of Hong Kong's 2019 protests may have contributed to the decision. "It's saddening...Hong Kong has completely changed," he added.

Ogawa began covering Hong Kong during the Umbrella Movement protests in 2014, which called for democratic change in the semiautonomous region, and wrote the book called "Chronicles of the Hong Kong Protests" that detailed the events surrounding the city's pro-democracy movement in 2019.

It was Ogawa's first trip to Hong Kong since February 2020, before the implementation of the Beijing-imposed national security law in June of that year, criminalizing acts of secession, subversion, terrorism and collusion with foreign forces.

In December, Japanese freelance photographer Michiko Kiseki, who previously hosted an exhibition featuring photos of the 2019 pro-democracy protests, was barred from entering the city.

Earlier this month, a Japanese busker known as Mr. Wally was also sent back to Japan by Hong Kong's authorities after being denied entry.