A woman was injured when her leg was slashed with a sharp object on a packed commuter train in Tokyo on Monday, the police said.

The 40-year-old victim, who was on her way to work, suffered an injury to her left thigh that will take three weeks to heal, the police said.

She noticed she was bleeding after feeling pain when she got off the JR Yamanote Line train at Osaki Station in Shinagawa Ward. Station officials called police at around 9 a.m.

The cut on the inner side of her thigh was about 10 cm wide and up to 3 cm deep, the police said.

They offered no details on a possible suspect.