Around 670 vehicles remained stranded Friday on a long stretch of highway northwest of Tokyo due to heavy snow, according to the road's operator, with police officers helping redirect vehicles to alternate routes.

Snow plows and other vehicles were deployed at hard-hit sections of the Kan-Etsu Expressway, which connects Tokyo and Niigata Prefecture, while members of the Ground Self-Defense Force continued their disaster relief work in affected areas after as many as 2,100 vehicles had been stranded on the highway.

As of 3 p.m., the 670 vehicles were stuck in the prefecture in the lane bound for Tokyo, according to East Nippon Expressway Co. The opposite lane also experienced congestion but that had eased by Friday morning.

"I hardly slept, and I was worried because I had absolutely no information (about the situation)," said a 48-year-old man who was driving to his home in Saitama Prefecture, near the capital, from Niigata Prefecture.

Food, fuel, blankets and portable toilets have been distributed to drivers of stranded vehicles. Some were caught in the snow on part of the highway between Niigata and Gunma prefectures on Wednesday night. The number of cars increased through Thursday, as those traveling behind were not able to avoid the congestion and snow continued to fall heavily.

Many people were forced to stay in their vehicles overnight as the year's most intense cold spell disrupted road and train services from Wednesday.

The Meteorological Agency forecast that heavy snow will continue to fall through Friday in the affected region, mainly in areas on the Sea of Japan coast, and warned that slippery roads could cause further traffic disruption.

According to the police and highway operator East Nippon Expressway Co., the line of cars stretched up to 16.5 kilometers at one point Thursday.