Mexico is closely monitoring Tropical Storm Ernesto, which could reach national territory on Tuesday or Wednesday, officials said.

The storm is gaining strength and could be a Category 1 hurricane by Monday night, the U.S. National Hurricane Center, or NHC, said in its latest bulletin.

Tropical Storm Ernesto was located about 305 kilometers (190 miles) east-northeast of Cabo Gracias a Dios, on the Nicaraguan-Honduran border, and some 655 kilometers (405 miles) east of Roatan Island, Honduras, at 11:00 a.m., the NHC said.

The storm, which has sustained winds of 100 kph (62 mph), is moving west-northwest at 15 kph (9 mph), the NHC said.

Ernesto's wind field could have a radius of up to 205 kilometers (127 miles) and cause waves of four meters (13 feet), the Mexican national emergency management office said.

"For now, Ernesto does not pose a danger to the country," the national emergency management office said.

The states of Quintana Roo, Yucatan and Campeche are on different levels of alert as the storm approaches, emergency management officials said.

Weather and navigation conditions may start deteriorating late Tuesday and worsen on Wednesday, the national emergency management office said.

Residents of areas in the storm's path should stay informed about the progress of Ernesto, the national emergency management office said.

"All of the Yucatan Peninsula should be watching the progress of 'Ernesto' due to the consistency of its track," the Mexican weather service said. EFE