A strong typhoon is approaching eastern Japan, prompting the country's weather agency to warn Tuesday of heavy rain, strong winds and high waves even before it reaches coastal areas in about two days.

Typhoon Shanshan, with an atmospheric pressure of 970 hectopascals at its center, was moving toward the Izu island chain, south of Tokyo.

As of 6 p.m. Tuesday, the year's 13th typhoon was about 390 kilometers east-southeast of Hachijo Island and moving at a speed of about 20 km per hour north-northwest, according to the Japan Meteorological Agency.

Intense rain is forecast on the Pacific side of eastern and northeastern Japan from Wednesday to Thursday due to the storm.

On Wednesday, All Nippon Airways will cancel six flights between Tokyo's Haneda airport and Hachijo Island and Jetstar Japan 19 flights throughout the country.

In the 24-hour period through Wednesday afternoon, 150 millimeters of rain may fall in eastern and central Japan, with a further downpour of up to 400 mm predicted in the following 24 hours.

On Thursday, the typhoon is expected to move north along the Pacific coast of northeastern Japan.