New fires have been seen blazing Monday in a forested area in north China's Inner Mongolia Autonomous Region and Heilongjiang Province, posing more difficulties for fire fighters as the previous one continued to spread.

Five more blazes, ranging from one to three square kilometers by 2 p.m., have been reported in Huzhong District and Tahe County of Heilongjiang, said Sun Xiguo, director of the fire control headquarters of Greater Hinggan Mountains.

The previous one, spotted Saturday afternoon in Inner Mongolia Autonomous Region and later spread to Heilongjiang, had engulfed an area of 17 square kilometers, Sun said.

More than 7,000 people from both Heilongjiang and another 3,000 from Inner Mongolia have been battling the fires.

The ground temperature had recently been as high as 50 degrees Celsius and coupled with a wind speed of 20 km/h, made battling the blazes extremely difficult, Sun said.

He warned the fires could converge with each other making them more difficult to isolate and control.

The air temperature had been at record high, more than 38 degrees Celsius since mid June, and there had been no rain for more than 10 days, said Guo Weiyan, a forest policeman of Inner Mongolia.

The dry hot weather will continue for the next three days, according to the Central Meteorological Bureau.

The fires were probably triggered by "dry lightnings," said Guo Wen, deputy chief of the meteorological observatory of Hulun Buir City, Inner Mongolia.

"Dry lightning is that which occurs without precipitation and is frequently seen in the forest area of the Greater Hinggan Mountains," Guo said.

Twenty-eight forest fires have been identified over the past four days in the Greater Hinggan Mountains, and more than ten were confirmed as caused by dry lightning, according to a statement issued Monday by the fire control headquarters of Inner Mongolia Forestry Management Bureau.

The Greater Hinggan Mountains is a large timber producing base in China, and is covered by more than 80,000 square kilometers of mainly pine forests.

Only forestry workers, who are participating in the fire control, live in the sparsely inhabited area. Their families have been evacuated, Sun said.

Chinese Vice Premier Hui Liangyu Sunday urged more efforts to be made to extinguish the fires quickly and ensure people's safety.