Protests outside a rally Donald Trump was holding in New Mexico turned violent as demonstrators threw burning T-shirts, plastic bottles and other items at police officers, and knocked down barricades.
During the rally, Trump was interrupted repeatedly by protesters, who shouted, held up banners including the messages "Trump is Fascist" and "We've heard enough".
Trump responded by instructing security to remove the protesters and mocking their actions by telling them to "go home to mommy".
It was the presidential candidate hopeful's first stop in New Mexico, the nation's most Hispanic state. Governor Susana Martinez, head of the Republican Governors Association and the nation's only Latina governor, has harshly criticised his remarks on immigrants and attacked his proposal to build a wall along the US-Mexico border.
Police responded by firing pepper spray and smoke grenades into the crowd outside the Albuquerque Convention Centre.
At one point, a female protester was physically dragged from the stands by security. Other protesters scuffled with security as they resisted removal from the convention centre, which was packed with thousands of cheering Trump supporters.
He called out one demonstrator by asking: "How old is this kid?", before providing his own answer: "Still wearing diapers."
The altercations left a glass door at the entrance of the convention centre smashed.
Governor Martinez did not attend the rally and has yet to make an endorsement.
The clashes came as Trump and democratic frontrunner Hillary Clinton each won primaries in Washington state.
Trump's victory helps him inch closer to clinching his party's nomination for president. He is within 41 delegates of the number needed to become the Republican nominee.