The United States will deny asylum to people who enter the country through a non-legal port of entry, President Donald Trump is likely to say on Thursday in remarks designed to enforce his hard line on immigration ahead of next week’s congressional elections.

The president’s remarks, plans for which were announced earlier on Thursday before a scheduled political rally later in the evening, will include his desire to change the asylum process, according to a source familiar with the matter.

The Immigration and Nationality Act provides that any immigrant in the United States may apply for asylum, regardless of whether he or she entered the country through a designated port of entry. Trump will insist that such applications be made at a legal point of entry.

Trump has ramped up his tough stance on illegal immigration, an issue that appeals to his core supporters, before elections on Tuesday that will determine whether his fellow Republicans keep control of Congress.

He will make his remarks at the White House at 4:15 p.m. (2015 GMT) on “the illegal immigration crisis and give an update on border security,” White House Press Secretary Sarah Sanders said in a statement.

In recent days, Trump has sought to present as a threat to the United States a large group of migrants from Central America who have left poverty and violence at home and are heading slowly through Mexico toward the U.S. border.

Republican Senator Chuck Grassley, an ally of the president and head of the powerful Senate Judiciary Committee, echoed some of the president’s strong rhetoric about the caravan in a letter to the secretaries of the Department of Homeland Security and the State Department.

In the letter, Grassley said his office had received information that several members of the caravan had “significant criminal histories” and was seeking information about “potential national security threats that reportedly exist among the members.”

Trump said on Wednesday the United States could send as many as 15,000 troops to the border to confront the migrant caravan, more than twice the number previously disclosed by defense officials.

Republican lawmakers and other Trump supporters have applauded the deployment. But critics argue Trump has manufactured a crisis to drive Republican voters to the polls.

On another immigration front, Trump said this week he would seek to scrap the constitutional right of citizenship for U.S.-born children of noncitizens and illegal immigrants, saying he would issue an executive order on so-called birthright citizenship.

Trump and some other Republicans say the right - granted by the Constitution’s post-Civil War 14th Amendment - creates an incentive for people to enter the country illegally to have children. Critics, including some other Republicans, say the president cannot change the Constitution by fiat. Such an action would virtually guarantee a legal challenge.