A hurricane which has already brought flooding to Mexico's Pacific coast has strengthened into a category four storm, forecasters say.
Hurricane Jimena, which is now rated as extremely dangerous, is moving slowly north-west, roughly parallel to the coast, meteorologists say.
On Sunday afternoon it had maximum winds of nearly 140mph (220 km/h).
Experts say it is on course to reach Mexico's Baja California peninsula by late Monday or early Tuesday.
Richard Pasch, of the National Hurricane Center in Miami, Florida, said it was difficult to predict how strong the hurricane would be when it neared the peninsula.
But he added: "I think it's going to be a substantial hurricane by the time it approaches."
One of the towns in its path is the resort of Los Cabos, where the Paris-based Organisation of Economic Co-operation and Development is due to hold a conference on Tuesday.
It was not clear if the conference would still take place.
US tourist Beverly Boyer said she planned to cut short her holiday in Los Cabos and fly home on Monday.
"I am nervous and frightened. This is a category four storm that is going to hit," she said.
On Sunday, authorities in Cabo Corrientes, a coastal town in the Mexican state of Jalisco, were setting up shelters in case of heavier wind and rain.