LOS ANGELES, May 29 (Xinhua) -- Hundreds of protesters took to the streets of downtown Los Angeles Friday night, clashing with police, during a third day of demonstrations over the killing of George Floyd.

Protesters marched in the streets, shouting slogans such as "I can't breathe" to express their anger over the killing of the unarmed Minnesota black man by police.

The march has mostly been peaceful amid heavy police presence. A police officer was attacked in the street and squad cars' windows were smashed by protesters, KTLA news channel, a local news outlet, reported.

Several people were detained for allegedly throwing objects at officers and damaging police cars, according to another local news outlet, City News Service.

A group of about 100 protesters reportedly blocked a major north-south freeway in downtown Los Angeles.

The Los Angeles Police Department urged people in a Tweet to avoid the Downtown Los Angeles area, including side streets and freeways, due to ongoing protests.

Demonstrations and riots have spread to cities across the United States after a video went viral of Floyd being suffocated to death by a white police officer in the mid-western state of Minnesota on Monday.