Transcript for Demonstrators surround Trump rally in Phoenix

So many demonstrations for and against president trump so let's go to our chief national correspondent Tom llamas there in the middle of all that chaos. Good morning to you, Tom. Reporter: Amy, good morning to you. Both sides showed up with massive crowds, but the Phoenix police department was ready. It was loud, it was hot and it was mostly peaceful but all that changed right at the end. We were right there as police in riot gear advanced on demonstrators outside of president trump's Phoenix rally. With moments of brief tension when protesters refused to leave the downtown area -- Reporter: -- Officers wearing gas masks armed with shields fired off tear gas. When demonstrators threw bottles and other projectiles, police used pepper spray to stop the assaults. You can see the Phoenix police department marching through downtown Phoenix and put tear gas in the air. They're also macing some people. Earlier police were able to keep the peace as several thousand demonstrators showed up surrounding the convention center where president trump held his rally. Phoenix police kept both sides separated but it didn't stop protesters from heckling trump supporters as they entered the rally. I'm really godsmacked the way that man has been acting in office. It's been nothing but total disorder. Reporter: But the president's strong support here showed in the lines that wrapped around the convention center. Many waiting 10 to 12 hours to hear the president speak. He is right about everything. We just need to support him as a country. Reporter: Now, the Phoenix police department again deserves a lot of credit because the tension was so high here and things could have been much worse. Most of the injuries were heat related and there was only a small number of arrests.

This transcript has been automatically generated and may not be 100% accurate.