A series of peaceful protests will be held across Mexico in defense of state-owned oil giant Petroleos Mexicanos, or Pemex, and against a supposed plan to turn the firm over to foreign oil companies, former leftist presidential candidate Andres Manuel Lopez Obrador said.

"We are going to defend the petroleum peacefully," Lopez Obrador said.

The leftist politician announced the protest plans during a rally staged by his National Regeneration Movement, or Morena, on Tuesday in Mexico City.

Lopez Obrador barely lost the 2006 presidential election and blamed his second-place finish in last year's vote on corrupt practices by the victorious Institutional Revolutionary Party, or PRI.

The "El petroleo es de todos" (The Petroleum Is Everyone's) campaign will hold its first demonstrations on Sunday, Lopez Obrador said.

Protests will take place in the plazas of cities across the country, with a rally planned for Mexico City, the leftist leader said.

President Enrique Peña Nieto said last month that Pemex would not be privatized and the public should be wary of those who sought to "mislead or confuse" the issue.

"No one, ever, has even referred to or cited the need for privatization," the president told a gathering of PRI and Mexican Green Party leaders on Jan. 30.

Leftist parties alleged recently that the government planned to privatize Pemex, which has a monopoly over the production of crude oil and distribution of gasoline.

Pemex, the world's No. 4 oil producer with output of about 2.5 million barrels per day, is the biggest contributor to Mexico's Treasury. EFE