Donald Trump signed the Laken Riley Act Wednesday afternoon as the president approves a series of initiatives meant to tackle his key goal of curbing illegal immigration.

The bill, which symbolically is the first bill Trump signed in his second term, requires that federal authorities detain immigrants who lack legal status and are accused of crimes, including several misdemeanor offenses, with the potential for deportation -- even before they are convicted.

"Today's signing is bring us one step closer to eradicating the scourge of migrant crime in our communities once and for all," Trump said Wednesday.

The Republican wish list item was passed with bipartisan support in both the House and the Senate and Trump campaigned heavily on curbing illegal immigration, using the death of Riley, a nursing student, as a centerpiece for immigration reform on the campaign trail.

"We will deport individuals based on the laws of this country. That's all this administration is trying to do enforce our nation's immigration laws," White House press secretary Karoline Leavitt said on ABC's "Good Morning America" on Wednesday.

"So if an individual is here illegally, if that means they cross our southern border illegally or they are overstaying their visa illegally or they've been deported before and returned to the U.S. illegally, which we found in many instances, they will be subject to deportation," she added.

While the bill indicates that authorities should detain those who are both present in the U.S. illegally and have been charged with a crime, the White House has argued that if someone is present in the U.S. illegally, he or she has committed a crime with Leavitt saying Tuesday, "And if you are an individual, a foreign national, who illegally enters the United States of America, you are, by definition, a criminal."

Riley, the namesake of the bill, was killed by Jose Ibarra, an immigrant without legal status first arrested in September 2022 on charges of illegal entry, outside Atlanta in February 2024. Her death fueled the immigration debate ahead of the 2024 elections.

"With today's action, her name will also live forever in the laws of our country," Trump said before signing the bill. "And this is a very important law. This is something that has brought Democrats and Republicans together. That's not easy to do."

Ibarra had been living in the U.S. illegally and had been arrested on misdemeanor shoplifting charges but was allowed to stay in the U.S. while his immigration case was ongoing. He was found guilty in Riley's murder in late 2024 and is serving a life sentence without parole.

"This horrific atrocity should never have been allowed to happen," Trump added Wednesday. "And as president, I'm fighting every single day to ensure that such a tragedy never happens again."

After Trump spoke, Riley's mother, Allyson Phillips, thanked Trump for supporting the bill.

"Our family will forever be grateful for the prayers of the people across our nation and for helping to get this legislation into law," she said. "[Trump] said he would secure our borders and that he would never forget about Laken, and he's a man of his word."

Key in the legislation is that it will require that the Department of Homeland Security "expeditiously take custody" of immigrants without legal status who are charged with burglary, theft, larceny, shoplifting or assault of a law enforcement officer, but not convicted.

Though several Democrats signed on to the legislation, many have argued the law is too extreme, with Wisconsin Sen. Tammy Baldwin saying the bill "authorizes the largest expansion of mandatory detention seen in decades for anyone even suspected or accused of shoplifting."

"Not only is this incredibly cruel and inhumane, it is also contrary to our legal system's bedrock principle that all individuals are innocent until proven guilty, and thereby wholly un-American," she added in a statement, noting that the bill could lead Immigration and Customs Enforcement officers "to prioritize indefinitely detaining people accused of petty shoplifting instead of going after suspected terrorists and violent offenders that pose a more urgent threat to the safety of our communities."

The law also allows attorneys general to sue the federal government if they can show states are being harmed by a failure to implement immigration policies and allows states to sue DHS for harm caused to citizens allegedly due to illegal immigration.

However, ICE has warned that enforcement of the bill will cost much more than the $3.2 billion initially expected -- and could reach $27 billion in its first year, according to a document obtained by ABC News.

"Full implementation would be impossible for ICE to execute within existing resources," the document noted, adding that ICE would need to expand its detention capacity to 151,500.

And that estimate from ICE only includes the Laken Riley Act, not other initiatives that are part of the Trump administration's immigration crackdown.

"We need Congress to provide full funding for the complete and total restoration of our sovereign borders, as well as financial support to remove record numbers of illegal aliens," Trump said.

Trump also signed 10 executive orders targeted at curbing illegal immigration in his first week in office, and newly confirmed Homeland Security Secretary Kristi Noem joined an immigration enforcement operation in New York City that resulted in the apprehension of several migrants lacking legal status on Tuesday.

"One of my top priorities is achieving President Trump's mandate from the American people to secure our southern border and fix our broken immigration system," Noem said on Saturday following her confirmation. "The Trump administration will once-again empower our brave men and women in law enforcement to do their jobs and remove criminal aliens and illegal gangs from our country."

And Trump said Wednesday he would also sign an executive order to permit the Department of Defense and the Department of Homeland Security to use Guantanamo Bay as a migrant facility.

"We have 30,000 beds in Guantanamo to detain the worst criminal illegal aliens threatening the American people," he said. "Some of them are so bad we don't even trust the countries to hold them because we don't want them coming back. So we're going to send them out to Guantanamo. This will double our capacity immediately."

ABC News' Lauren Peller, Allison Pecorin and Armando Garcia contributed to this report.