MORIOKA (Kyodo) -- Japan's disaster management agency on Sunday requested more fire departments across the country to join the battle against a forest fire that has continued to spread in the northeastern prefecture of Iwate.

Nearly 1,700 firefighters from around 450 departments across the country have already joined the effort to control the blaze, which has spread over five days since Wednesday in Ofunato, according to the Fire and Disaster Management Agency.

The agency has newly asked the governments of Hokkaido and Yokohama city to dispatch some of their firefighters to Ofunato.

While firefighters with aerial support from helicopters, including those of the Self-Defense Forces, have managed to keep the flames from spreading toward Ofunato's residential areas along the Pacific coast, nearly 1,800 hectares of land had been burned as of Sunday, an increase of 400 hectares since the previous day.

The city has so far issued evacuation orders to around 4,600 residents, with over 1,200 people staying in shelters as of Sunday morning.