According to the National Center for Hydro-Meteorological Forecasting, it now lies on the Laos border with maximum wind speeds of 40 kph.
No loss of life has been reported.
It will move west-northwest at a speed of 15-20 kph.
Under the storm's influence, provinces along the central strip from Quang Tri to Binh Dinh have received rainfall of up to 350 millimeters in several places starting Thursday morning.
The Central Highlands provinces of Kon Tum and Gia Lai recorded more than 150 mm in some places.
Provinces lying between Ha Tinh and Thua Thien Hue are expected to get rainfall of 80-150 mm on Friday.
Dinanmu is the sixth storm to enter the East Sea so far this year.