A 31-year-old Hong Kong man was arrested on suspicion of assaulting a Japanese couple in Tsim Sha Tsui East, police said on Wednesday morning.
He was picked up by police in Hung Hom at about 11pm on Tuesday. He was released on bail and is required to report back to police later this month.
The attack occurred around 8pm on Monday when a Japanese businessman, Tatsuya Akioka, 37, and his wife, Miwa Akioka, 35, were walking from their home in Hung Hom to Tsim Sha Tsui.
At the Tsim Sha Tsui East Promenade, a man approached them and asked in English if they were Japanese. He then punched them and fled.
The pair were treated in hospital for injuries to their legs, shoulders and heads, and were discharged.
After the attack, the Japanese consulate in Hong Kong condemned the violence and demanded the Hong Kong government ensure the safety of Japanese people and companies.
The attack came amid escalating anti-Japanese protests across the mainland this week over the sovereignty of the Diaoyu Islands, known as the Senkakus in Japan. In some rallies, violent demonstrations vandalised cars, shops and businesses with Japanese ties.
The assault also happened on the eve of the 81st anniversary of the Mukden Incident – an explosion staged by Japan and used as a pretext for its invasion of China.
The Yau Tsim Mong district crime squad is still investigating the assault.