Signal failure disrupted Seibu Shinjuku Line services in Tokyo on Friday morning, affecting 168,000 rush-hour commuters, the railway said.

The suspension of train services between Seibu Shinjuku and Tanashi stations came after signals turned red at around 3:20 a.m. and crossing gates came down along the line, according to Seibu Railway Co.

While the operations resumed shortly after 10 a.m., the carrier said the cause of the malfunction remains unknown.

At Takadanobaba Station, Yasushi Sakurai, a 47-year-old businessman from the city of Saitama, said he might have to miss a sales talk, while a high school student said, "We called our school and were told to come by bus."