Police report small explosion forces closure of California court

A California court was sealed off Wednesday after a homemade bomb exploded, with media in the western US state reporting a man had thrown some kind of device in an apparent protest.

Police in Santa Maria said one man had been arrested at the scene and two people had been injured.

"Santa Maria Courthouse: report of an explosion. Please avoid the area. Scene has not been deemed safe," the Santa Barbara County Sheriff posted on social media.

"We have two reports of non-life threatening injuries. One person of interest detained immediately.

"Explosion was from an intentionally set improvised explosive device."

Local media reported witnesses saying a man had arrived at the courthouse around 8:30 am (1530 GMT) shouting in an apparent protest, and had dropped something that began emitting smoke, sending bystanders running.

Staff working in offices near the court told AFP they had not seen or heard anything, and only became aware of the apparent explosion when informed by law enforcement.

The United States is on heightened alert weeks ahead of a bitterly contested presidential election.

An apparent assassination attempt on Republican Party candidate Donald Trump was foiled earlier this month after the gunman's rifle was spotted poking out of some bushes at his Florida golf club.

The courthouse in Santa Maria was the scene of popstar Michael Jackson's lengthy 2005 trial on child abuse charges.