LOS CABOS, MEXICO (AFP) - Mexican authorities have declared a "red alert" for the popular resort region of Los Cabos as Tropical Storm Bud closed in on the coast, whipping it with wind and rain.

Under the measure, the highest level of alert, authorities will evacuate some 9,000 people from areas at high risk of flooding and other damage, said the head of emergency services for the state of Baja California Sur, Carlos Alfredo Godinez, on Thursday (June 14).

"We are evacuating families from high-risk zones, by force if we have to," a local official in Los Cabos, Luis Alberto Gonzalez, said in a briefing.

With its turquoise water and picturesque beaches, the Baja California peninsula in northwestern Mexico is a hot vacation spot for Americans and Canadians.

Authorities ordered the closure of the two airports that serve the Los Cabos area, including the international airport, which handles more than 100 flights a day.

An estimated 21,000 tourists are currently in hotels in the resort towns of Cabo San Lucas and San Jose del Cabo, in the Los Cabos area at the tip of the peninsula, according to state tourism minister Luis Araiza.

He said the hotels had implemented safety protocols.

Schools were closed in Los Cabos and state capital La Paz.

Bud was poised to make landfall near Cabo San Lucas, travelling at 11km per hour, with maximum sustained winds of 75km per hour, according to the US National Hurricane Centre.

It was expected to cross the Baja California peninsula overnight, then move over the Gulf of California on Friday, hitting mainland Mexico as a tropical depression on Friday night or early Saturday before dissipating.

Bud was a category four hurricane on Tuesday, but has weakened as it has approached land.