Republican presidential nominee says he will institute a tracking system to ensure immigrants who overstay their visas are removed.

U.S. Republican presidential candidate Donald Trump on Saturday offered new details of how he would tackle illegal immigration, saying he would crack down on those who overstay their visas.

Speaking in Des Moines, Iowa, and quoted by Reuters, Trump sought to clarify his views on how to overhaul the U.S. immigration system after saying earlier in the week that he was softening on his plan to deport all 11 million illegal immigrants.

That stance drew fire from conservatives who wanted him to stand fast after he won the Republican presidential nomination in large part by a hardline stance that would include building a wall along the U.S. border with Mexico.

In his speech on Saturday, Trump said he would seek to institute a tracking system to ensure illegal immigrants who overstay their visas are quickly removed, and would propose an e-verify system to prevent the illegal community from gaining access to welfare and other benefits.

"If we don’t enforce visa expiration dates, then we have an open border – it’s as simple as that," he said, according to Reuters.

"Every time an African-American citizen, or any citizen, loses their job to an illegal immigrant, the rights of that American citizen have been violated," he continued. "Equal protection under the law must include the consistent application of our immigration laws."

Trump added that his first priority upon taking office next January would be the immediate deportation of thousands of illegal immigrants who remain in the United States despite having committed crimes.

"These international gangs and cartels will be a thing of the past. Their reign of terror will be over. In this task, we will always err on the side of protecting the American people – we will use immigration law to prevent crimes, and will not wait until some innocent American has been harmed or killed before taking action," he was quoted by Reuters as having said.

He did not explain how his plan would affect many of the illegal community who have been in the United States for decades and obeyed U.S. laws.

Earlier this month, Trump gave a fiery speech in which he promised to institute “extreme vetting” of immigrants to protect the nation from radical Islamic terror, as part of his plan for fighting terrorism.

“The common thread linking the major Islamic terrorist attacks that have recently occurred on our soil…is that they have involved immigrants or the children of immigrants,” he said in a speech in Youngstown, Ohio.

“We should only admit into this country those that share our values and respect our people. We will be tough, and we will be even extreme,” Trump added.

While Trump has been criticized by some for his immigration policy, a recent poll found that immigrants and immigrant families have a higher support for Trump immigration policies than the rest of the American population.