The five remaining American presidential hopefuls are drumming up support from voters days before two more primaries and one state's caucuses measure their popular support. As usual, Republican front-runner Donald Trump has been generating controversy and attention.
Protesters tried Saturday to stop a Trump rally in Arizona near the Mexican border by leaving their cars in the middle of a street and blocking traffic. Some held up a banner reading "Dump Trump." Three people were arrested.
Demonstrators assemble outside the Trump International Hotel and Tower during an anti-Donald Trump protest in New York, March 19, 2016.
In his speech, Trump again pledged to build a wall along the border to keep out illegal immigrants, who he says bring drugs and violent crime into the U.S.
He accused his Republican rivals, Texas Senator Ted Cruz and Ohio Governor John Kasich, of being weak on immigration and also pledged to keep jobs and U.S. industries from going to Mexico.
He said China was able to build its economy on American money and jobs, calling it one of the world's greatest robberies.
Another anti-Trump protest took place Saturday in New York City outside the Trump Tower office building on Fifth Avenue.
Democratic presidential candidate Bernie Sanders gives a news conference near the U.S.-Mexico international border at Nogales, Arizona, March 19, 2016. He pledged to fight for immigration reform.
Sanders at border
Democratic underdog Bernie Sanders, a Vermont senator, also campaigned Saturday along the Arizona-Mexico border, but his remarks were much less caustic than Trump's.
Sanders promised to end what he called inhumane deportation programs and said his immigration reform plan would quickly pave the way for citizenship for 11 million undocumented immigrants while also ensuring security along U.S. borders.
Tuesday's primary in Arizona is another winner-take-all contest for the Republicans. That means the candidate who gets the most votes also gets all of the state's delegates, rather than having to divide them up with the trailing candidates.
Trump already has more than half the delegates needed to secure the nomination, which worries Republican leaders who fear the straight-speaking and often harsh Trump cannot win the White House and will damage the party's unity.
For the Democrats, former Secretary of State Hillary Clinton has a huge lead in the delegate count over Sanders, who continues to rely on his large support among young voters to try to stage a comeback.
Utah also holds its primary Tuesday, while Democrats will caucus in Idaho.