Colombia's left-wing guerrilla group, the Revolutionary Armed Forces of Colombia (FARC), planted thousands of landmines across swaths of the country during its five-decade war against the government.
"Forty percent of the areas that were covered in landmines for the past 25 years are now being cleared to reach the goal of having a Colombia free of anti-personnel mines by 2021," Rafael Pardo, the government's post-conflict commissioner, told local media Monday.
After Afghanistan, Colombia has the second-highest number of landmine casualties, with more than 11,500 people killed or injured by landmines since 1990, government figures show.
The FARC rebels planted homemade mines in mostly rural areas, using empty glass bottles of rum, coffee and tuna cans, and plastic tubes filled with sulfuric acid.
In 2015, the government and FARC rebels agreed to work together to remove landmines during peace talks in Cuba.
Under the December peace accord, around 6,300 FARC fighters have so far moved to designated areas across Colombia where they will hand in their weapons over the next six months.
The government hopes that nearly 1,000 former FARC combatants will work to identify and clear mines, Pardo said.
With the FARC moving away from their former strongholds, it is now safer for government military demining teams, along with local and international demining groups, to work in new areas.
Colombia's president, Juan Manuel Santos, has said clearing landmines is a key challenge facing the nation as it emerges from decades of war and is crucial for rural development.
Experts say Colombia's mountainous and jungle terrain make mine clearance difficult, and it will take Colombia at least a decade to rid the country of all its landmines.
International donors, including the United States and Norway, have so far contributed nearly $112 million for landmine clearance in Colombia.