Fueled by high winds and drought, wildfires starting more than one month ago continue burning in US state of New Mexico, threatening more communities in the Rocky Mountain foothills while forcing some local schools going virtual.

The wildfires have burned more than 318 square miles (824 square km) of ponderosa forests across the state, destroying about 300 structures, Xinhua news agency reported, citing the local media reports.

In northern New Mexico, officials at the Los Alamos National Laboratory and residents in the nearby town are prepared to evacuate if a wildfire burning there moves closer, said the reports.

The cost of fighting the blaze and another smaller fire burning near the Los Alamos National Laboratory has topped $65 million so far, an ABC News report said on Tuesday.

Nearly 1,800 firefighters and support personnel have been assigned to fight the blaze, said the report.

The state's governor, Michelle Lujan Grisham, said at a briefing on Tuesday that she had not received any reports in recent days of widespread damage to homes but believed the risk of more destruction is high.

The US National Weather Service has issued red flag warnings for extreme fire danger in much of New Mexico and parts of Nevada, Arizona, Colorado and Texas this week.

The wildfire season in the region normally starts in May or June but this year is dangerously early, CNN Meteorologist Monica Garrett said last month, noting New Mexico in April has already seen a year's worth of fire activity.

Wildfires have become a year-round threat in the drought-stricken US West and they are moving faster and burning hotter than ever due to climate change, US scientists and fire experts say.