Puerto Rican Gov. Alejandro Garcia Padilla (R). (Thais Llorca/European Pressphoto Agency)

Hours before Puerto Rico missed hundreds of millions of dollars of bond payments, U.S. Treasury Secretary Jack Lew on Monday issued a new and urgent call for Congress to pass legislation allowing the territory to restructure the $72 billion it owes to creditors.

In a letter to House Speaker Paul D. Ryan (R-Wis.), Lew connected the island’s fiscal crisis to the mosquito-borne Zika virus, which has spread through the Caribbean and was recently confirmed to have claimed its first life on U.S. soil — a 70-year-old Puerto Rican man who died in February from a bleeding disorder linked to Zika.

“This is not just a matter of financial liabilities and litigation,” Lew wrote. “Hospitals continue to lay off workers, ration medication, reduce services, and close floors. Moreover, despite the intensifying threat from the Zika virus, financial constraints have made it extremely difficult to counteract. Unsealed septic tanks, abandoned homes, cemeteries, and piles of old tires, where mosquito larvae grow, for example, must all be treated, but the government is struggling to pay for the work to be done.”

The Government Development Bank, which acts as a fiscal agent to Puerto Rican municipalities, owed $422 million to bondholders by the close of business on Monday. It paid interest but no principal Monday on those loans, though a group of credit unions agreed to forego $33 million of payments in exchange for new bonds that expire in a year. Some GDB creditors said Monday they would be willing take a significant loss and defer upcoming payments, but it could be impossible to get all of those creditors to agree to such a plan. The island is pushing for a court-managed restructuring created by act of Congress to force a swift and orderly process.

FILE - In this Wednesday, July 29, file 2015 photo, the Puerto Rican flag flies in front of Puerto Rico’s Capitol as in San Juan, Puerto Rico. Puerto Rico Gov. Alejandro Javier Garcia Padilla said on Sunday, May 1, 2016, that negotiators for the U.S. territory’s government have failed to reach a last-minute deal to avoid a third default and that he has issued an executive order to withhold payment. (AP Photo/Ricardo Arduengo, File) The Puerto Rican flag flies in front of  the Capitol in San Juan, Puerto Rico in this 2015 photo. (Ricardo Arduengo / AP)

Monday’s default pales in comparison to the expected default on July 1, when $2 billion worth of debt service payments come due.

The House Natural Resources Committee is drafting legislation that, in its latest form, would give public borrowers on the island the ability to petition a judge to restructure their debts in a process akin to bankruptcy in conjunction with the imposition of a fiscal control board that would oversee the territory’s revenue collection and spending. But the legislation remains in limbo, with many Republicans fearing that a territorial bankruptcy process might eventually be extended to states, while Democrats are pushing for a more streamlined path to a court restructuring, as well as the removal of several controversial policy provisions from the bill.

A spokeswoman for Ryan, AshLee Strong, said “discussions continue” among the various parties involved in the legislation and praised the committee’s chairman, Rep. Rob Bishop (R-Utah), for “crafting a solution to address Puerto Rico’s debt crisis in a timely and fiscally responsible way.”

Lew, in his letter, said that the remaining issues were “few” but important. “Small changes in text would address these issues in a fair and acceptable way,” he said.

And he renewed warnings that, absent congressional intervention, the fiscal crisis could accelerate to the point that direct federal aid to the island might become necessary. Advocates of a restructuring bill have had to combat the perception that any congressional action would constitute a “bailout,” even though there would be no taxpayer funds expended under the current proposals.

Other voices have joined in recent days in calling for Congress to act: Alejandro García Padilla, the governor of Puerto Rico, in an address delivered Sunday, blamed “vulture funds and their lobbyists” for waging “a brutal campaign of racial discrimination and lies.”

“We have asked Congress in many occasions to give us the tools to restructure our financial liabilities,” he said. “We do not want a bailout. We haven’t asked for a bailout. We haven’t been offered a bailout. . . . We simply want the legal tools needed to address our insolvency crisis and ensure the sustainability of Puerto Rico.”

And on Monday, the U.S. Conference of Catholic Bishops weighed in on behalf of Puerto Ricans. “Her people are United States citizens, and leaders have an obligation to address their unique circumstances with urgency and justice,” wrote Thomas G. Wenski, the archbishop of Miami and chairman of the conference’s Committee on Domestic Justice and Human Development.

The Government Development Bank on Monday said it tentatively rescheduled about $900 million of debt with a group of creditors willing to accept a 43.75 percent reduction in the face value of their bonds, and an exchange of their old bonds for new ones that won’t come due for some time. The creditors, who are known as the Ad Hoc Group and include several hedge funds, agreed to hold off on any legal actions related to the payments due Monday and continue to negotiate the detailed terms.

But the deal would require 100 percent participation from other bondholders, Puerto Rican credit unions and other institutional investors, something virtually impossible to win over.

“Without federal restructuring legislation, including the tools to bind non-consenting creditors, the transaction would be highly unlikely to reach the required participation levels,” the GDB said in a statement. “In the absence of federal legislation, the GDB would not be able to complete the deal as proposed, and the Commonwealth as a whole would not be able to move towards a comprehensive restructuring of the island’s debt.”

Steven Mufson contributed to this report.