LOS ANGELES (KABC) -- Crowds protesting the Ferguson, Missouri grand jury decision marched through Los Angeles Tuesday night, forcing the closure of the 101 Freeway in downtown Los Angeles at Grand Avenue.Just after 9 p.m., protesters spilled into lanes of the 101 Freeway at Grand Avenue and blocked traffic in both directions using barricades and debris collected from surface streets. No injuries were reported, but two women were handcuffed and detained.Police quickly corralled those on the freeway. Other protesters congregated on the Grand Avenue overpass before officers forced them across the bridge.The protesters had broken away from a larger group of hundreds who had marched through city streets and to Los Angeles Police Department headquarters.Earlier at about 3 p.m., a demonstration in Leimert Park, organized by the Youth Justice Coalition, marched eastbound down Martin Luther King Jr. Boulevard in Leimert Park toward the LAPD Southwest station east of Western Avenue. Protesters shouted, "Hands up, don't shoot."Shortly before 7 p.m., a crowd of about 300 was moving northbound on Figueroa Street toward Pico Boulevard. By 8 p.m., large crowds had gathered in front of the LAPD Administration Building at 100 West 1st Street.Crowds also gathered on Martin Luther King Jr. Boulevard at the 110 Freeway briefly, but were stopped by a large police presence. Police were holding the on- and off-ramps secure at the scene to prevent people from marching onto the freeway as happened Monday night. Marchers then began moving northbound on Martin Luther King Jr. Boulevard.At one point, protesters could be seen surrounding a police car and jumping on top of it.One police officer was injured after he was struck in the head with a frozen water bottle.The LAPD was on citywide tactical alert for the second consecutive day. The citywide tactical alert allows the LAPD to keep officers on duty beyond their normal shifts.Monday night, protesters filled the streets in downtown L.A. and even blocked the 110 Freeway "We're still angry and frustrated. We believe Michael Brown was murdered by officer Darren Wilson," Project Islamic Hope's Najee Ali said Tuesday.During a Tuesday news conference, LAPD Chief Charlie Beck thanked the majority of demonstrators who did not break the law."We want to make sure everybody knows that we absolutely support the First Amendment, we support people's right to assemble and to lawfully speak out on issues that are a great concern to them," Beck said. "We cannot support and we will not allow people to use their rights to trample on the rights of others."The LAPD had initially lifted its first tactical alert overnight, and said three people were arrested in the downtown protests for public intoxication, failure to disperse and attacking an officer."This is a national discussion, a national debate, on police legitimacy and on issues of race. It's an important debate. It's an important discussion to have," Beck said. "But we want to have that discussion in a manner that puts forth the ideals that people are trying to express and not in a manner that detracts from them."Los Angeles city officials said that overall the demonstrations were peaceful."I was very impressed and proud of the way that Angelenos acted last night," said Los Angeles City Councilman Herb Wesson.However, Beck said demonstrations on the freeways will no longer be tolerated for safety reasons."It's not only dangerous for the protester, it's dangerous for the motoring public and dangerous for the public safety employees that will risked their lives to make sure that the other people involved are safe," Beck said. "We will make arrests if people go up on the freeway."