BOGOTA, Colombia (AP) — Colombian presidential front-runner Gustavo Petro pledged on Monday that he will not expropriate private property if he wins the nation’s presidency this year as critics in the South American country accuse the leftist candidate of wanting to make radical changes to the country’s economy.

Petro made the electoral promise in a public notary in Bogota, where he signed a document that said that “nothing or nobody will be expropriated” if he becomes president. In the document, Petro said he was obliged to make the unusual pledge, because his campaign has been tarnished by “lies and fear mongering.”

“The campaign for profound and true change in Colombia is being attacked constantly with rumors and misinformation,” the document read. “With clarity, I affirm that my proposal to transform this country is not based on, or includes any kind of expropriation.”

As the presidential race in Colombia enters its final month, Petro’s opponents have accused him of wanting to implement economic policies similar to those of Hugo Chavez. The former Venezuelan president nationalized dozens of industries, eroded the independence of his country’s central bank and imposed exchange controls as he vastly increased the government’s role in the economy.

In recent years, almost two million Venezuelans have fled to Colombia to escape their country’s economic troubles — including hyperinflation and the lowest wages in South America — which makes comparisons to Venezuela relevant among many voters in Colombia.

In presidential debates, Petro, who formerly described Chavez as a “great Latin American leader,” has distanced himself from the Venezuelan economic model, affirming that it relied too heavily on oil income. He’s added that if he becomes president he would like to promote alternative sources of energy and agricultural growth.

Petro is currently leading presidential polls in Colombia as the country reels from high unemployment rates, growing rates of poverty and a sluggish recovery from the pandemic that led to massive protests last year.

The senator obtained an 11 point lead over his closest rival in a survey conducted during the first week of April by the Centro Nacional de Consultoria polling firm, but is still short of the 50 percent required to win the May 29 election without a run off.

Petro leads a coalition of leftist parties known as the Historical Pact that has promised to increase corporate taxes, slow down oil exploration and put tariffs on some imported goods, to benefit local farmers.

German Navas, a law professor and congressman for the leftist Polo Democratico party, said on Colombia’s Blu Radio that the document signed by Petro at the notary on Monday is not legally binding, but is meant to clarify his positions.

In his campaign manifesto Petro does not mention the word expropriation but has promised to “democratize” access to land in Colombia by increasing taxes on large rural estates that are deemed unproductive.

The candidate has said that landowners who do not wish to pay the new fees can instead hand some of their land over to the government as payment. It will then be distributed among landless peasants or people who were displaced from their villages by decades of violence in the countryside.

Petro has also promised to reform the nation’s pension system by transferring the savings of people making less than two monthly minimum wages from privately run companies into a state-owned pension fund. The changes would shake up the pensions system, as they would affect a majority of the nation’s contributors, and some critics have likened them to nationalizing pension funds.

Petro said that these changes would help to provide payments to millions of people who are currently not covered by the system.