Barely a week after Hurricane Harvey devastated large swaths of the US Gulf coast, Americans on the East Coast on Sunday were warily watching the progress of another major storm, Hurricane Irma.

For now, those fears are mostly speculative, as the Category 3 storm remains far out in the Atlantic. Its track is, as the Weather Channel described it, "still uncertain and difficult."

But some forecasters projected a turn north that could target a large swath of the heavily populated mid-Atlantic region on the East Coast.

The US National Hurricane Center, in an advisory issued at 11 am (1500 GMT), said the storm has maximum sustained winds of 115 mph (185 kph), with some strengthening expected during the next 48 hours.

It cautioned those in the Leeward Islands -- situated where the northeastern Caribbean meets the western Atlantic -- to "monitor the progress of Irma," adding that parts of those islands might face hurricane or tropical storm watches by evening.

The islands, also known as the Society Islands, have a population of just over 30,000.

But as to "Hazards Affecting Land" from Irma, the NHC said Sunday that, for now, there were "none."

Source: AFP