Hillary Clinton and Donald Trump each were the projected winners in the respective Democratic and Republican primaries in Arizona, one of three western states voting on Tuesday.
Clinton trounced Bernie Sanders in the state, while Trump held a huge lead over rival Ted Cruz.
Caucuses were being held in Utah, and Democrats were caucusing in Idaho. Results were slow to come in as long lines were reported at caucus sites.
On the Republican side, Trump was poised to expand his lead, as he collected all of the state's 58 delegates as it is a winner-take-all state. Cruz is expected to win in Utah, and could win all of the state's 40 delegates if he ekes out a majority, but that could be stymied if John Kasich makes a showing. Trump was more than 300 delegates ahead of Cruz.
In Seattle on Tuesday, Clinton said that the response to the terrorist attacks required leadership that is "strong smart, and above all steady."
"The last thing we need are leaders who incite more fear," she said.