President Trump on Tuesday urged Congress to get to work on legislation to replace the Obama-era program known as DACA, as his administration is expected to wind down the policy that protects young illegal immigrants who came to the U.S. as children.

Attorney General Jeff Sessions is scheduled Tuesday morning to announce the fate of the Deferred Action for Childhood Arrivals program. Sources say the administration plans to end the program, with a six-month delay.

The delay would allow Congress time to craft a legislative solution, instead of the executive action former President Barack Obama used in 2012 to enact the program.

“Congress, get ready to do your job – DACA!” Trump tweeted Tuesday morning.

An estimated 800,000 people brought to the United States when their parents arrived illegally are in the program.

Trump is under pressure to end DACA from Republican state attorneys general who say the program is unconstitutional and are threatening a legal challenge.

Putting the issue to Congress could end the legal threat, while leaving the program's future unclear.

Democrats oppose ending the program and argue any change would put those already in the country at risk of being deported and hurt the economy.

Republicans are largely split on the issue, with some wanting immediate action and others seeking a legislative solution that curtails the program and protects those already here -- potentially with strings attached.

South Carolina GOP Sen. Lindsey Graham backs Trump’s plan while urging Congress to take matters into its own hands.

“I have always believed DACA was a presidential overreach,” Graham, who is part of bipartisan legislation on the issue, said Monday. “However, I equally understand the plight of the Dream Act kids who -- for all practical purposes know no country other than America. If President Trump makes this decision we will work to find a legislative solution to their dilemma.”

Rep. Steve King, an Iowa Republican and immigration hawk, wants an immediate end to DACA.

“Ending DACA now gives chance 2 restore Rule of Law,” he tweeted this past weekend. “Delaying so R Leadership can push Amnesty is Republican suicide.”

House Speaker Paul Ryan, R-Wis., has said DACA is unconstitutional but also has expressed sympathy for those in the program. On Friday, he told a Wisconsin radio station that he wants DACA to continue until Congress finds a legislative solution.

Other congressional Republicans like Arkansas Sen. Tom Cotton have suggested legislation ending DACA as part of a more comprehensive immigration-reform package that includes more border security and tighter immigrant vetting.