Arizona Gov. Doug Ducey offered rare Republican support Wednesday for President Trump's threat to close the Mexico border if Congress doesn't pass comprehensive immigration reform.

"I think our trade with Mexico is extremely important, but border security comes first," Ducey told reporters on the White House driveway after meeting with Trump.

Ducey said that Trump has not made a decision, but that if he does close the border, "we would be supportive of it — and want it to be as short as possible."

He added: "Why doesn't Congress just act and we can solve the whole issue?" Ducey said he wants funds for border security, more money for nonprofits, and legal changes to remove "incentives" to migrants.

Trump last week threatened to close the border if Mexican authorities didn't disrupt Central American migrant caravans. When authorities made arrests, Trump abruptly said Tuesday that he may still close the border if Congress does not pass a long list of controversial immigration reforms.

"I could do it in 45 minutes. We need to get rid of chain migration. We need to get rid of catch and release. And visa lottery. We have to do something about asylum. And to be honest with you, have to get rid of judges," Trump said Tuesday.

Many Republican critics of Trump say that international trade is too important to justify a border closure.

[Related: Avocado prices surge as Trump threatens to close border with Mexico]

Some of the reforms requested by Trump previously were sought in exchange for a pathway to citizenship for young illegal immigrants who have work permits under the Deferred Action for Childhood Arrivals program, which will be reviewed by the Supreme Court.

Trump, who visits southern California on Friday, surprised many fellow Republicans in December by triggering a 35-day partial government shutdown over a demand that Democrats fund a Mexico border wall, which they refused to do.