BEND, Ore. -

A human-caused brushfire broke out Monday afternoon on vacant land in northeast Bend, prompting a multi-agency response and a search for witnesses to the early stages of the blaze.

The fire was first reported in three trees in a field off Holiday Avenue northwest of St. Charles Medical Center around 2:40 p.m.

The blaze quickly brought response not just from Bend fire crews but the Oregon Department of Forestry and U.S. Forest Service, Deschutes County 911 dispatchers said.

No structures were involved and no evacuations reported, although two blocks of Holiday Avenue were closed and ash reportedly fell on some vehicles parked at St. Charles Medical Center-Bend.

Bend fire Battalion Chief Dave Howe said crews found a slow-moving fire, burning in junipers and sagebrush.

The nearest structure was about 50 yards away, Howe said, as the fire moved in a southeasterly direction.

With help from mutual-aid partners, he said, the fire was held to about eight-tenths of an acre.

In an update Tuesday morning, Deputy Fire Marshal Jeff Bond said fire investigators were unable to find an exact cause of the fire but did find it to be human-caused, having ruled out natural causes.

Bend fire and police investigators are still following up on witnesses, he said, and anyone with information was asked to contact Deschutes County dispatchers at (541) 693-6911. You can also contact the Crime Stoppers Tip Line at 1-877-876-TIPS, or use the form on KTVZ.COM's Crime Stoppers page. You can remain anonymous, and you could receive a cash reward.

Howe reminded residents that grass and brush is very dry and flammable at this time of year.

"With no rain in the forecast, we expect burning conditions to identify over the next couple of weeks," he said.