Conservative candidate Abelardo de la Espriella won Colombia’s presidential runoff election on Sunday after months of intense campaigning, defeating left-wing rival Iván Cepeda in one of the country’s most closely contested elections in recent years.

With 49% of the vote, De la Espriella secured victory in the runoff, according to preliminary election results.

De la Espriella, a lawyer and controversial figure in Colombian politics, has been involved in several high-profile legal cases. He previously represented members of Colombia’s self-defense forces accused of crimes against humanity and also served as defense attorney for businessman Alex Saab.

A central pillar of De la Espriella’s campaign was a pledge to wage an all-out offensive against Colombia’s guerrilla groups until their complete defeat. He has proposed the construction of 10 large-scale prisons modeled after El Salvador’s Terrorism Confinement Center (CECOT) and the expansion of military operations, including aerial strikes against guerrilla positions.

His platform also includes conservative policies on public security and governance, including measures aimed at making civilian firearm ownership more accessible.

Outgoing President Gustavo Petro questioned the election process following the vote and alleged irregularities. As of Sunday evening, Petro had not formally recognized the results.

Election authorities have not announced any evidence supporting claims of widespread fraud or irregularities.