The last of three credit rating agencies has downgraded Puerto Rico's debt by two notches to junk status.

Fitch Ratings on Tuesday praised the U.S. territory for responding quickly to economic challenges but noted the economy remains weak and its access to the bond market is impaired.

Puerto Rico is preparing to re-enter the market and has assured investors that it will not default on $70 billion in public debt.

The announcement comes one day after Gov. Alejandro Garcia Padilla announced measures to help boost the U.S. territory's economy as the island of 3.7 million people battles its eighth year in recession and a 15.4 percent unemployment rate, higher than any U.S. state.

Standard & Poor's has downgraded Puerto Rico's credit by one notch and Moody's by two notches.