MORIOKA (Kyodo) -- A massive wildfire in northeastern Japan has continued to spread, burning around 3,000 hectares, despite the first rainfall on Wednesday since it broke out a week ago.

The forest fire in Ofunato, Iwate Prefecture, has burned 9 percent of the city's total area. While rain is expected through Thursday, firefighting efforts have been hampered by heavy snow and strong wind alerts, the local weather bureau said.

The Ofunato municipal government said it has instructed more than 4,500 residents from about 1,900 households to evacuate.

Prime Minister Shigeru Ishiba told parliament Wednesday that designating the fire a "disaster of extreme severity," which would boost central government subsidies for local recovery and reconstruction, is "in sight."

"We will ensure a swift and appropriate response so that disaster victims can feel at ease and the financial burden on the local government is minimized," Ishiba added.