The government of Puerto Rico released the details of its plan to restructure the commonwealth's massive debt and satisfy creditors' demands on Feb. 1, but the island's creditors was questioned by one bond insurer.

Under the proposal developed by the Working Group for the Fiscal and Economic Recovery of Puerto Rico, the island would reduce its outstanding obligations by about $22.7 billion, from $49.2 billion to $26.5 billion, the official body said in a statement. Annual repayments would also be capped to 15 percent of government of government revenue, the working group added.

Supposed 'partners in growth' say plan is not 'serious'

Puerto Rico argues that the cap in particular would make creditors "partners in the island's future growth," and a so-called "base bond" would also give them better legal protections. But Ambac, a company that insured $2.2 billion of Puerto Rico bonds as of the end of November 2015, immediately called the plan unworkable, CNBC reported.

"We do not view this proposal as a serious effort," Nader Tavakoli, Ambac's president and chief executive officer, told the business channel. Further, the CEO lamented that it was "difficult to engage in discussions since Puerto Rico refuses to share basic information" about its fiscal situation and its steps to address its dire economic situation.

Leaders in San Juan hope for help from Washington

Nevertheless, advisers of Puerto Rican Gov. Alejandro García Padilla unveiled the plan on Jan. 29 at a meeting with representatives of the creditors, and Padilla's administration is also hoping to get some political backing from Washington for its efforts, the Washington Post pointed out.

Lawmakers in Congress and officials from the Obama administration are currently looking into legislation that could help Puerto Rico restructure its debt or even give the commonwealth access to bankruptcy protection it does not currently enjoy, the newspaper pointed out.

That, in turn, could force creditors to sign onto a plan despite the significant cuts they would be taking, the Washington Post speculated.