Donald Trump announced Thursday that he would reverse the order of President Joe Biden to clamp down on border crossings. This was his first public appearance since a New York Court found him guilty last week of 24 felonies.

He also threatened to impose tariffs against countries that did not stop the flow of immigrants into the United States. This is part of his effort to capitalize on a topic that polls have shown resonates with Americans.

When asked by an audience at an Arizona event that was a must-win, what Trump would do to stop the flow of migrants entering the U.S. through the southern border – including those from China and the Middle East – he said he’d use economic measures.

He said: “We have tremendous power economically… If China or another country behaves badly, we can impose tariffs which are very severe.”

He added: “We’re going be so tough, and if that country doesn’t behave, then we will tariff them to hell,” without revealing the size or type of tariffs.

Trump was in Phoenix to attend his first public event since he was convicted on 34 counts of falsifying records of business to conceal a payment of hush money to a pornstar who claimed they had sexual relations years before Trump became president.

After a lengthy speech, a sympathetic audience in this border state on the southwest coast was given the chance to ask questions to the former president.

Most of the questions were variations of the theme of immigration. Polls indicate that this is the most important issue in the minds of voters ahead of the 5 November election.

Biden issued this week an executive order to bar migrants from entering the US illegally claiming asylum if their numbers exceed 2,500 per day.

This order makes it easier for people to be deported back to Mexico.

The curbs are to remain in place as long as the number of illegal crossings per day does not fall below 1,500.

Biden was criticized by all sides because of the new policy, which used the same law Trump had previously used to ban immigrants from Muslim countries while he served as president.

Republicans meanwhile, called it too little.

Trump said on Thursday that he would reverse this order if he were to win the election.

He told the crowd that he would rescind Crooked Joe’s outrageous executive orders on Day 1 of his administration. Without providing any evidence, he called it “pro-invasion… pro-child trafficking… and pro-drug dealers.”

“And I will end every open border policy of the Biden Administration.”

Biden’s victory in Arizona in 2020 was by just 10,000 votes. The state will be critical to both men if they want to win another four years at the White House.

Trump will hold a rally on Sunday in Nevada, a swing state.