Trump Maintains Hardline Immigration Stance: 'We'll Build a Great Wall'

Republican presidential nominee Donald Trump made it clear during a speech in Arizona Wednesday night that he plans to stick with his hard stance on immigration.

"We will build a great wall along the southern border," he said to a cheering audience. "And Mexico will pay for the wall."

Trump outlined a set of proposals for tackling illegal immigration, promising to focus first on deporting illegals who have committed crimes.

"Zero tolerance for criminal aliens. Zero. Zero. Zero. They don't come in here, they don't come in here." Trump said. "According to federal data, there are at least 2 million -- 2 million, think of it -- criminal aliens now inside of our country... We will begin moving them out day one as soon as I take office, day one."

Under his presidency, Trump said there would be "no amnesty," adding that no illegal immigrant will be legalized without first leaving and coming back the correct way.

"It is our right as a sovereign nation to choose immigrants that we think are the likeliest to thrive and flourish and love us," Trump said.

He also promised to cancel President Barack Obama's executive actions and enforce current immigration laws.

This all comes on the heels of a surprise trip to Mexico by the Republican nominee. In a meeting with President Enrique Peña Nieto, Trump defended the right of the United States to build a border wall.

"It was a thoughtful and substantive conversation and it will go on for a while, and in the end, we're all going to win. Both countries. We're all going to win," Trump said.

He added that the two men did not discuss who would pay for the cost of the wall, but Mexico's president later tweeted: "At the start of the conversation with Donald Trump I made it clear that Mexico will not pay for the wall."

Hillary Clinton also took to Twitter to blast Trump's visit to Mexico, tweeting: "Trump just failed his first foreign test. Diplomacy isn't as easy as it looks."

Clinton took the stage at an event in Ohio to say that Trump is not a leader.

"(It) takes more than trying to make up for a year of insults and insinuations by dropping in on our neighbors for a few hours and then flying home again. That is not how it works," Clinton said.

But in the polls Trump is still closing the gap with Clinton. According to a new Fox News poll, the two are virtually tied in a four-way race, with Clinton at 41 percent and Trump at 39 percent.

Meanwhile, Clinton's unpopularity is reaching new heights, with the latest ABC News/Washington Post poll showing she's now tied with Trump among registered voters.

But with the critical presidential debates yet to come, a lot can still happen in the two months between now and Election Day.