SAN JUAN, P.R. — Gov. Ricardo A. Rosselló of Puerto Rico said on Monday that the island was on the brink of a “humanitarian crisis” nearly a week after Hurricane Maria knocked out its power and most of its water, and left residents waiting in excruciating lines for fuel. He called on Congress to prevent a deepening disaster.

Stressing that Puerto Rico, a United States commonwealth, deserved the same treatment as hurricane-ravaged states, the governor urged Republican leaders and the federal government to move swiftly to send more money, supplies and relief workers. It was a plea echoed by Puerto Rico’s allies in Congress, who are pushing for quick movement on a new relief bill and a loosening of financial debt obligations for the island, which is still reeling from a corrosive economic crisis.

“Puerto Rico, which is part of the United States, can turn into a humanitarian crisis,” Governor Rosselló said. “To avoid that, recognize that we Puerto Ricans are American citizens; when we speak of a catastrophe, everyone must be treated equally.”

And Mr. Rosselló did not mince words about the potential impact on the mainland, where Puerto Ricans are expected to arrive in droves to escape the post-Maria hardships they will face on the island, including a shortage of already hard-to-find jobs.