How progressive.

(KOIN) — A man is under arrest after a police officer was injured during a clash with Occupy Portland protesters when an incendiary device was thrown at a group of mounted riot officers early Sunday morning.

Sometime after 1:30 a.m., what looked like a firework was thrown into a group of mounted officers who were trying to push the crowd off Main Street.

A few moments later, police pulled a man out of the crowd and arrested him. He was identified as 23-year-old Cameron Scott Matta.

The officer, who was not on a horse when he was hit by the device, was transported by ambulance to a local hospital. He is expected to be OK, according to Portland police.

Matta was booked in the Multnomah County Jail on one count each of disorderly conduct in the second degree, misdemeanor harassment and interfering with a peace officer, also a misdemeanor. He is being held on $5,500 bail.