President Donald Trump on Monday will ask the U.S. Congress for an additional $8.6 billion to help pay for the wall he promised to build on the southern border with Mexico to combat illegal immigration and drug trafficking, said officials familiar with his 2020 budget request.

The demand is more than six times what Congress allocated for border projects in each of the past two fiscal years, and 6% more than Mr. Trump has corralled by invoking emergency powers this year.

Democrats, who oppose the wall as unnecessary and immoral, control the U.S. House of Representatives, making it unlikely the Republican President’s request will win congressional passage. Republicans control the Senate.

Regardless of whether Congress passes it, the budget request could help Mr. Trump frame his argument on border security as the 2020 presidential race begins to take shape, with the President seeking re-election. Funding legislation needs to be passed before October 1 — the start of the 2020 federal fiscal year — or the government could shut down again.