Paris, Jul 5 (IANS/EFE): Mexican authorities should investigate "the obstructions, censorship and intimidation that may have affected the coverage and observation of the electoral process", said the Paris-based press-rights group Reporters Without Borders, or RSF, said.

"Right up to the eve of election day, the campaign was marked by numerous attacks on journalists and also on observers, bloggers and campaigners for electoral transparency such as members of the #YoSoy132 collective," RSF said in a statement Wednesday.

Sunday's presidential election was won by Institutional Revolutionary Party, or PRI, candidate Enrique Pena Nieto, who garnered 38.14 percent of the vote, according to the final preliminary results released by the Federal Electoral Institute, or IFE.

"Much of the violence has been attributed to supporters of the three main candidates, starting with backers of the man who has been proclaimed the winner, Enrique Pena Nieto, leader of the Institutional Revolutionary Party that led the country continuously from 1929 to 2000. The fact that the candidate of the left, Andres Manuel Lopez Obrador, has asked the Federal Electoral Institute for a recount could further increase tension," RSF said.

The press rights group called on Mexican media outlets to take a stand "against escalation and partisan attacks that could polarize still further a bruised and divided society".

"In addition, the organization hopes for the early clarification of the circumstances of the death of the 22-year-old American journalist Armando Montano, whose body was found in an elevator shaft at his apartment building on 30 June. Among the stories covered by Montano, an intern in the Mexico City bureau of the Associated Press news agency, was the killing of three federal police officers at the capital's Benito Juarez airport on 25 June," RSF said.