Mexican Congresswoman Dolores Padierna of the Democratic Revolution Party, PRD, is blocked by riot police as she tries to make her way to the National Congress in Mexico City, Monday August 14, 2006

Mexico's top security official has rejected claims of police brutality a day after riot police clashed with demonstrators protesting last month's disputed presidential election.

Public Security Minister Eduardo Medina Mora Tuesday defended Mexican police who fired tear gas at protesters outside Congress. He expressed regret about the confrontations but said they were, in his words, "inevitable."

Riot police blocked off streets around the Congress today to prevent further incidents.

Several protesters, including at least two federal lawmakers, were injured in Monday's clash. It was the first violent confrontation since the start of protests in support of leftist presidential candidate Andres Manuel Lopez Obrador.

Riot police prevent supporters of Mexican presidential candidate Andres Manuel Lopez Obrador from getting to the National Congress in Mexico City

The former Mexico City mayor is demanding a recount because of alleged fraud in the election that he narrowly lost to his rival, conservative Felipe Calderon.

The Federal Electoral Tribunal ordered a recount in nine percent of the country's 130,000 polling places. The recount has been completed but the results have not been made public.

On Sunday, Lopez Obrador threatened more protests if electoral officials declare Calderon the winner. The court has until September 6 to declare a president-elect.

Some information for this report was provided by AP and Reuters.