Mexico City's former mayor has officially registered as a candidate in next year's presidential election.

Andres Manuel Lopez Obrador signed up as a candidate for the Democratic Revolution Party's nomination Saturday, making him the first person to register with the party.

Mr. Lopez Obrador addressed hundreds of supporters outside party offices, just one day after he stepped down as the capital city's mayor.

The popular 51-year-old leads public opinion polls ahead of the 2006 presidential race.

President Vicente Fox is not eligible to run for re-election because Mexican law allows just one six-year term.

Some information for this report provided by AP and AFP.