Republican vice presidential nominee campaigns in Denver Wednesday, Aug. 3, 2016.

(Vic Vela/CPR News)

Republican vice-presidential nominee Mike Pence spoke to supporters in Denver Wednesday, trying to make the case for Donald Trump.

Pence, who is Indiana’s governor, attacked Democratic presidential nominee Hillary Clinton as being weak on economic and foreign policy.

“For the sake of our security, for the sake of our prosperity, let’s decide here in Colorado that Hillary Clinton will never be elected president of the United States of America” he said.

Pence also said Trump would appoint U.S. Supreme Court justices opposed to abortion and backed the Second Amendment. Ane he attacked the media for making too much of Trump’s controversial comments. 

“The media and the Democrats, it seems like… something new comes up every couple of days, doesn’t it? Hourly. And they keep telling each other, they keep saying, ‘Now we got ‘em.’ They think the usual methods are going to work against him,” Pence said. “He’s going to fight all the way into November and deliver a great victory for the people of Colorado and the people of the United States.

But Pence declined to echo Trump's claim on Wednesday that the election could be "rigged."

A man in the audience at a rally in Denver on Wednesday said Hillary Clinton had stolen delegates from Bernie Sanders and asked Pence what the campaign was going to do to prevent her from stealing the election. Pence didn't comment on the claim and said the campaign was working closely with state elections officials across the country to "ensure ballot integrity."

He urged Trump supporters to volunteer to help at the polls to make sure the election is conducted fairly.

Earlier in the day Pence broke with the Republican nominee by endorsing House Speaker Paul Ryan in his primary fight.

Pence said in a phone interview with Fox News Channel that he's pleased to endorse Ryan — a day after Trump said in an interview that he's "just not quite there yet" when it comes to backing Ryan, who has at times been critical of Trump's most controversial comments.

Pence says that he spoke with Trump Wednesday morning about his "support for Paul Ryan and our longtime friendship."

He says Trump, "strongly encouraged me to endorse Paul Ryan in next Tuesday's primary. And I'm pleased to do it."

The Associated Press contributed to this report.