Mayor of Mexico City told he can run for president

In an attempt to defuse a growing political crisis, the Mexican President, Vicente Fox, has said that the leading candidate for next year's election - the left-wing Mayor of Mexico City - should not be prevented from campaigning.

In an attempt to defuse a growing political crisis, the Mexican President, Vicente Fox, has said that the leading candidate for next year's election - the left-wing Mayor of Mexico City - should not be prevented from campaigning.

Mr Fox said that Mayor Andres Manuel Lopez Obrador should be allowed to carry on working while an investigation into his alleged refusal to obey a judge's order was investigated. Under Mexican law anyone facing charges cannot run for office.

Mr Fox's spokesman, Ruben Aguilar, said that while prosecutors would not drop abuse of power charges against Mr Lopez Obrador, the government would not try to stand in his way as the case progresses.

"The solution that has to be found in a judicial way - and it will be a challenge for the new Attorney General - is to allow other eyes to analyse the files and find routes so no case keeps Mr Lopez Obrador [out of the presidential race]," he said.

The move on Thursday followed a surprise announcement on Wednesday night by Mr Fox when he said he was accepting the resignation of his Attorney General, Rafael Macedo de la Concha, whose office had sought to prosecute Mr Lopez Obrador. The Attorney General's deputy also resigned following wide-spread claims that the prosecution of the Mayor was fuelled by political rather than legal concerns.

Mr Lopez Obrador has long said that Mr Fox's administration was pursuing the charges simply to keep him out of the race. "I have always maintained that the impeachment is a political matter and not judicial. That is how the majority of Mexicans see it," he said.

The immediate crisis stemmed from a decision by Congress to strip the Mayor of his immunity from prosecution to face charges that several years ago he failed to obey a judge's order to stop building a hospital access-road on private land. Many observers believe the offence - if indeed one was committed - was little more than a technicality and certainly did not warrant a criminal prosecution.

But behind the decision by Congress lies a desire by many conservatives to prevent Mr Lopez Obrador, the leading candidate, assuming power in next year's election. By law, Mr Fox is prevented from running for office for a second time.

Ironically, rather than hurting Mr Lopez Obrador, the case has made him more popular with many would-be voters who think the charges against him are unfair.

On Sunday, hundreds of thousands of people filled Mexico City's central plaza to show him their support.

At stake in next year's election is whether the country will join other countries in the region, such as Venezuela, Brazil and Uruguay, in electing a leftist leader. Some observers believe the crisis will be the sternest test yet for Mexico's nascent democracy. When Mr Fox was elected in 2000 he ended 71 years of rule by the Institutional Revolutionary Party.