LOS ANGELES — Democratic presidential candidate Bernie Sanders is breaking with the Obama administration and House lawmakers over a plan to restructure Puerto Rico’s $70 billion in debt, saying the legislation would make “a terrible situation even worse.”

The Vermont senator writes in a letter released Monday that the deal reached last week between the White House and House Republicans and Democrats would empower an “unelected and undemocratic oversight board” and allow the governor of Puerto Rico to slash the minimum wage to $4.25 an hour for up to five years.

“We must stop treating Puerto Rico like a colony and start treating the American citizens of Puerto Rico with the respect and dignity that they deserve,” Sanders wrote in a letter to Senate colleagues.

“At a time when the people of Puerto Rico are suffering, the legislation introduced in the House would make a terrible situation even worse,” he wrote.

Sanders trails Democratic rival Hillary Clinton in the presidential primaries and both are competing in the upcoming June 5 Puerto Rican caucuses. Clinton has outperformed Sanders among Latino voters during the primaries.

Sanders has been virtually absent from Senate proceedings during his lengthy primary campaign but his opposition could complicate the measure’s future after careful negotiations between the White House and House Speaker Paul Ryan.