Puerto Rico's situation could get worse without Congress' help, said Raul Maldonado, the island's Treasury secretary.
In a phone interview with CNBC.com, Maldonado said Puerto Rico's government will run out of money by the end of the month if the U.S. legislature does not send emergency funds its way.
The cash shortage would lead to a government shutdown and would hinder Puerto Rico's efforts to aid its residents after Hurricane Maria ravaged the island.
"If we don't get the help we need, this will be a national disaster," Maldonado said. "We're not looking for a handout; we're just looking for some help to get back on our feet."
Maria, a Category 4 storm, left most of Puerto Rico's 3.4 million residents without electricity and water and destroyed the homes of thousands. It also took out much of the island's telecommunications infrastructure.
Puerto Rico was already dealing with a massive financial crisis before the hurricane hit it. The island holds more than $70 billion in debt in part because of years of government overspending.
Puerto Rico also has been contending with a dwindling population in recent years, reducing its tax base. The island's population shrank 8.4 percent between 2010 and 2016, according to the U.S. Census Bureau. The mass exodus from Puerto Rico could accelerate after Hurricane Maria hit the island two weeks ago.