Supporters of Andres Manuel Lopez Obrador, who narrowly lost Mexico's presidential election, held a mass rally in the capital's main square.

They have been calling on incumbent President Vicente Fox to order a full recount of votes.

Many accuse Mr Fox and his successor Felipe Calderon of stealing the election.

The crowd voted by a show of hands to swear Mr Lopez Obrador in as "legitimate president".

Some analysts believe creating a parallel administration will reduce the threat of violence.

Earlier in the day, Mr Fox attended a military parade on the same square.

Mr Fox was cheered by his own supporters, but a few opponents held up placards.