Confusion in Mexico over time changes

A decision by the mayor of Mexico City to refuse to bring the clocks forward with the rest of the country has sparked a constitutional crisis.

On Monday, the mayor, Andres Manuel Lopez, said the federal government didn't have the power to change the hour across the country.

But the president's office issued a statement saying Mr Lopez' move was unconstitutional.

Mexico's federal government said the time change would save millions of dollars in energy costs. Opinion polls in Mexico City indicate that most people in the capital dislike the time shift, but also oppose having a different time from the rest of the country.

From the newsroom of the BBC World Service