Mexican conservative presidential candidate Felipe Calderon declared victory last night in a bitterly contested election, but his leftist rival vowed to challenge the result.
Presidential candidate Felipe Calderon claims he has won the election
Mr Calderon had a lead of around 400,000 votes over Andres Manuel Lopez Obrador with returns in from more than 98 per cent of polling stations. A senior election official said that lead was unlikely to change with a recount ordered for later this week.
A Calderon victory would ensure Mexico sticks to the free-market policies of outgoing President Vicente Fox and hold steady as a US ally, bucking a trend of Latin American nations that have turned to the left and away from Washington in recent years.
But Mr Lopez Obrador said his team had found irregularities in the preliminary vote count and he planned to file a legal challenge.
"This preliminary result is full of errors, it does not show what we consider the reality and we cannot endorse it," he said at his campaign headquarters. "We are going to take this to the corresponding legal authorities. We will be responsible."
A drawn-out battle could spark a political deadlock reminiscent of the US 2000 election and strain Mexico's young democracy. The close outcome has also raised fears of unrest.
In television and radio interviews, a confident Mr Calderon of the ruling National Action Party said his lead was irreversible and called on political rivals to put aside differences.
"Today all of Mexico, I dare say the whole world, knows who won," he said. "The election is behind us and now the time has come for reconciliation and unity among Mexicans."