The US territory of Puerto Rico announced on Thursday the implementation of a water rationing system, as it faces a drought and a long-standing worsening shortage in water supplies that prompted the governor to declare a state of emergency.

Luis González, executive director of the Puerto Rico Water and Sewer Authority, said that thousands of people in the northeastern area of the island will be subject to water rationing for 48 hours starting Friday.

The water rationing program will include a number of neighborhoods and residential communities in the cities of Canóvanas and Río Grande, as temperatures continue to rise.

He said: 'Simply put, there is not enough water,' adding that the rationing measures will likely be expanded to other areas.

González attributed the crisis to low rainfall, although a severe shortage in water supplies began affecting some of the island's most densely populated areas months before the drought started, while officials have not yet been able to determine the cause of the problem.

Those interruptions prompted the mayor of San Juan to file a lawsuit against the Puerto Rico Water and Sewer Authority in late May, while the island's governor, Jennifer González, acknowledged that the authority's infrastructure has suffered from a lack of investment and maintenance for decades.