Tropical Storm Maria strengthened on Sunday and is predicted to become a hurricane as it moves toward the Lesser Antilles and Puerto Rico, which are already preparing for its arrival in the coming days.

  The storm, which has maximum sustained winds of 100 kilometers (62 miles) per hour, is en route to the Lesser Antilles, some 655 km away and which were recently lashed unmercifully by Hurricane Irma.

  The islands, including Puerto Rico and Cuba, were all seriously affected by Irma - with more than 90 percent of the island of Barbuda devastated by the storm, according to local authorities - and reconstruction is under way throughout the region.

  The potential threat posed by Maria is materializing just a week after Hurricane Irma's passage through the Caribbean, after which it went on to move up the spine of the Florida Peninsula, killing more than 30 people in US territory and causing untold damage.

  In the Florida Keys, over which Irma passed, bringing significant destruction to the low-lying islands, tens of thousands of residents who evacuated prior to the storm were just returning to their flooded and damaged homes.

  Authorities in Monroe County, where the Keys are located, have asked residents returning to the area to bring with them enough provisions to meet their needs for a time, given that basic services - including electricity, potable water and sanitation - are not fully restored.

  The eye of Irma made landfall last Sunday on Cudjoe Key as a Category 4 storm with maximum sustained winds of 215 kph, after which it moved up the southwestern coast of Florida, causing significant damage and flooding in cities such as Naples and even Miami and Jacksonville, which are on the eastern coast of the state.

  On Saturday, Monroe County authorities confirmed that at least nine people had died there from causes attributable to Irma, and on Sunday 37 percent of the homes and offices there have no electricity, while statewide some 675,000 power company customers still are without electricity, although 93.5 percent of those who lost power during the storm have regained it.

  In Miami-Dade County, the state's most populous county, meanwhile, 11 percent of the population still has no electricity, but authorities have announced that classes will resume on Monday after schools have been closed since Sept. 6 due to the storm.

  Another eight people died in a Hollywood nursing home, north of Miami, after the storm due to high temperatures and no air conditioning.