Followers of Lopez Obrador’s Democratic Revolution Party occupied motorway toll booths to give motorists free entry to Mexico City and blockaded government offices as party officials said the protests would grow.
“Until now we have concentrated an important part of our protests in the capital, but in this new stage we are going to carry out actions all over the country,” Guadalupe Acosta, the party’s secretary general said.
Acosta said the protests "will be coordinated, national actions with the same objective: that they open the boxes and count the votes”.
Supporters of Lopez Obrador, who claims vote counts were fiddled at more than half of the country's 130,000 polling stations, want all the votes cast in the closey-contested July 2 presidential elections to be recounted.
Election officials will begin a partial recount of ballots on Wednesday.
The protests began in early July when Lopez Obrador narrowly lost the presidential election by 244,000 votes.
The close result led thousands of Lopez Obrador’s supporters to take to the streets accusing the ruling party of rigging the elections.
Lopez Obrador won 35.31% of the vote while Felipe Calderon of the ruling National Action Party won 35.88%.
The Democratic Revolution Party formally requested a full recount of all the votes, but the electoral court said such a move would break Mexican law.
Instead electoral officials will review the ballots at nine percent of the country's 130,000 polling places. The recount is scheduled to end on Sunday.
However, Lopez Obrador and his party have continued to demand a full recount of all the ballot papers.
Lopez Obrador has vowed that protests will continue
"We are going to carry on our struggle. ... We are sure we will triumph," Lopez Obrador told demonstrators gathered in the capital's central plaza on Tuesday night.
On July 31, several hundred thousand people occupied Mexico City’s main square and surrounding roads to show their support for Lopez Obrador.
The seizure of the motorway toll booths on Tuesday prompted the spokesman of Vicente Fox, the outgoing President to threaten demonstrators with force for the first time.
But demonstrators backed off before that could happen, abandoning the toll booths shortly after the end of morning rush hour.
President Fox criticized the protests, saying that “democracy cannot advance without respect for others and above all without respect for institutions”.
Hundreds of activists also blockaded the entrance to offices of federal agriculture department in Mexico City for more than six hours on Tuesday.
The Federal Electoral Tribunal has until September 6 to declare a president-elect or annul the election.
Fox is scheduled to leave office on December 1 after completing a single, six-year term.
The recount is expected to confirm that Lopez Obrador’s rival, Felipe Calderon, should become Mexico’s next President.