BOGOTA (Reuters) - The number of people killed or wounded by landmines in Colombia more than tripled in 2018 to 180, a landmine monitoring group said on Wednesday, as militants occupying territory abandoned by demobilized leftist rebels have expanded their use of the weaponry.

The casualties, compared with 56 in 2017, were mostly in jungle and mountain areas previously controlled by the Revolutionary Armed Forces of Colombia (FARC) rebels, who demobilized last year under a peace deal with the government to end five decades of war.

As FARC members returned to civilian life, much of the drug trafficking and illegal mining territory they previously controlled has been occupied or fought over by criminal gangs, dissident rebels who did not lay down arms and the smaller rebel group the National Liberation Army (ELN).

“This year we have had an increase of more than 200 percent in people who have suffered accidents with mines, many with dramatic injuries,” said Alvaro Jimenez, the director of the Colombian Campaign Against Landmines, which detailed the casualties in a report.

“We need to sound the alarm because we can’t allow Colombia to return to being among the countries most affected” by landmines, Jimenez said.

The majority of victims were civilians, the report said, a change from previous years when many were military personnel.

The FARC traditionally warned civilian populations about mined areas, while current armed groups have largely not, the report said.

Colombia cleared 2 square kilometers (0.77 square miles) of landmines since the peace deal was signed in late 2016.

Colombia, a signatory of the Ottawa Convention, which prohibits the production and use of landmines, has pledged to remove them by 2021.

Given the current dynamic of the conflict, that target looks unlikely, the report said, and Colombia will likely have to set a new date or ask for a 10-year extension.