At least 37 urinals across 16 parks in the Japanese city of Sapporo have been hit by the thief, whose motivation is unclear, TV station UHB reports.

The metal grates are worth around 1,000 yen (about €6 or £5) each, police said.

The thefts took place over the course of two weeks at the tail end of May and were first noticed by city cleaners.

The urinals have been repaired and police are stepping up patrols in parks in a bid to catch the thief.