WASHINGTON — President Donald Trump on Friday began sketching a roadmap for dismantling the Education Department, with other agencies taking over responsibility for federal student loans and programs serving students with disabilities.

The executive order Trump signed Thursday to do away with the department did not offer a timeline or instructions, but his administration appears poised to carve away all but the department’s most vital operations.

The Republican president said during a White House event that student loans will be handled by the Small Business Administration, and “it will be serviced much better than it has in the past.” He also said programs involving students with disabilities would be shifted to the Department of Health and Human Services.

The decisions drew blowback from advocacy groups that fear disruptions will be inevitable. The Small Business Administration announced Friday it will cut its staff by 43%, raising questions about its ability to take on the Education Department’s $1.6 trillion loan portfolio.

“This can only result in borrowers experiencing erratic and inconsistent management of their federal student loans,” said Jessica Thompson, senior vice president of the Institute of College Access and Success. “Errors will prove costly to borrowers and ultimately, to taxpayers.”

Trump’s executive order said the student loan portfolio is too big for the Education Department to manage. After the SBA cuts, however, it will be left with fewer than 4,000 employees — about the size of the Education Department before it was cut in half by the Trump administration.

Education Secretary Linda McMahon said she is preparing to relocate the department’s core operations to other agencies and roll back federal regulations. In an opinion piece published Friday by Fox News Channel, she said abolishing the department “will not happen tomorrow,” but she plans to pave the way.