Inside the property, the entertainer, who has a history of legal problems, posted videos to social media declaring his innocence.

The call came in around 3am local time from outside the sprawling hillside property in the San Fernando Valley area, according to police spokesman Chris Ramirez. He did not say what assistance the woman needed.

"Detectives are trying to make contact with Mr Brown," he said. They also want to talk with the woman and any witnesses, he added.

Police were waiting for a judge to approve a search warrant, officer Lyle Knight said. Several police cars were parked outside the home.

Meanwhile, Brown posted a least three online videos dismissing TV reports that he was barricaded inside.

"I don't care. Y'all gonna stop playing with me like I'm the villain out here, like I'm going crazy," Brown said in one Instagram video, waving a cigarette and looking at the camera.

"When you get the warrant or whatever you need to do, you're going to walk right up in here and you're going to see nothing. You idiots."

Brown, who won a Grammy for his 2011 album F.A.M.E., has been in repeated legal trouble since his felony conviction in the 2009 assault of his then-girlfriend, Rihanna. After several missteps, he completed his probation in that case last year.