A raging wildfire in Arizona that has forced nearly 10,000 people from their homes has now spread across the border into New Mexico.

Firefighters have made some progress against the blaze, with six percent of it contained, an improvement since early Thursday when the fire was “zero percent” contained.

Crews were bracing for strong winds Saturday after lighter winds boosted their efforts to slow the fire's spread.

More than 1,500 square kilometers has burned since the fire began several weeks ago. The blaze has sent smoke as far east as the state of Iowa, and has forced planes to divert course.

The fire is the second largest in Arizona's history. Authorities have not yet determined its cause, but many wildfires are started by human activity.