By Jessica Michele Herring (staff@latinospost.com) | First Posted: Nov 13, 2013 02:11 PM EST

A homemade bomb exploded into flames outside a courthouse early Wednesday in the town of Medford, Ore. A propane tank was rigged up as a homemade bomb, Reuters reports. No one was hurt and the damage was minimal, police said. 

Details of the blast are still coming in, but Medford police Lieutenant Mike Budreau said that officers were called to the Jackson County courthouse at around 4:30 a.m. local time (7:30 EST) to investigate a reported explosion. 

They found that a damaged seven-gallon propane tank had combusted, in addition to broken glass from shattered windows. The court house was only damaged on the outside, Budreau said. 

"We believe the suspect tried to detonate the propane tank with an improvised explosive device (that) damaged the propane tank," he said. He said that the tank caught fire, but it remained mostly intact. 

No arrests have been made, and the motive behind the bombing is still unknown. 

"We're not sure if this is targeted towards a prosecution that was going to happen or has happened or whether it's something else," he said. He said the investigation was "wide open at this point."

According to an account from the Medford Mail Tribune newspaper, police reported an unidentified male in dark clothing seen several blocks from the the blast who ran away from an officer when he was approached. 

Federal agents and Oregon state police are working with local police in the investigation, authorities said.