Police in Phoneix say they were pelted with bottles and rocks thrown by anti-Trump protestors following Tuesday night's rally. The police then deployed tear gas to disperse the crowd. According to Arizona's 12News, the police also used flash bangs and pepper balls in an effort to break up the crowd. The tear gassing began less than 10 minutes after Trump finished his speech.

"Police said protesters threw bottles and rocks at police in the area.” 12News live blog: https://t.co/iG9CCQFMyO — Leigh Munsil (@leighmunsil) August 23, 2017

Protestors were present before and during the rally as well.

Yahoo's Hunter Walker managed to get a video of the police gassing the crowd. According to Walker, the protestors were screaming "This is not a riot!"

Police are gassing the crowd and running in. People are screaming "This is not a riot!" pic.twitter.com/1vgZVwBmbF — Hunter Walker (@hunterw) August 23, 2017

A photo taken by CNN shows the street post-tear gas.

Photo taken of street post-tear gas by CNN's @Bob_Ortega pic.twitter.com/YvuepaBHrZ — Saba Hamedy (@saba_h) August 23, 2017

Other images and videos taken outside the rally appear to show a small riot as well as the police deploying tear gas.

Phalanx of police fired tear gas at protestors right outside our building #TrumpInPhoenix pic.twitter.com/447UymPIof — John D'Anna (@azgreenday) August 23, 2017

Full scale riot going on in Phoenixpic.twitter.com/HKRceKpm6j — Tennessee (@TEN_GOP) August 23, 2017

It is currently unclear as to what specific incident prompted the use of tear gas by police.