Human rights groups estimate that violent clashes between armed groups in the Catatumbo region have displaced more than 32,000 people.

Colombia's president has issued a decree giving himself emergency powers to restore order in a region bordering Venezuela that has been racked by deadly violence that erupted between rival armed groups.

Gustavo Petro issued a decree on Friday giving him up to 270 days to impose curfews, restrict traffic and take other measures that would normally violate the rights of Colombian citizens or require congressional approval, the Associated Press reported.

It applies to the rural region of Catatumbo in northeastern Colombia, which borders Venezuela.

Since mid-January, violence has surged in the region between National Liberation Army (ELN) rebels and Revolutionary Armed Forces of Colombia (FARC) dissident groups, who are fighting for control of drug trafficking routes.

At least 80 people have been killed in recent weeks and more than 32,000 have been forced to flee their homes, according to human rights groups. Residents say armed groups are carrying out indiscriminate attacks from house to house.

Last week, Petro's government announced the suspension of peace talks with the ELN as violence intensified in Catatumbo.

The leftist president, who takes office in 2022, has promised to bring "comprehensive peace" to the South American country after decades of conflict between the state, paramilitaries and rebel groups.

Petro pushed for negotiations with armed groups, and his tactics reduced violence. But rebel infighting and clashes with the Colombian army persist.

The government has deployed thousands of troops to Catatumbo in an attempt to stem the latest violence. Wednesday, office Colombia's attorney general also reissued an arrest warrant for the leader of the National Liberation Army.

It said in a statement that it would "rescind the benefit of the moratorium on the arrest of 31 (ELN) representatives... who have been recognized by the national government as spokespersons for the negotiations".

The ELN denies attacking civilians and says its attacks target former FARC rebels and demobilized rebels who support them.

The FARC was once the country's largest rebel group, but multiple groups splintered off after a 2016 peace deal largely disbanded the group. They have also recently entered into peace talks with Petro's government.

Human rights groups have urged the government to ensure civilians in Catatumbo are protected.

"We call on the Colombian authorities to urgently take all necessary measures to protect civilians in the Catatumbo region, including human rights defenders," Amnesty International said, warning of "the growing threat of imprisonment, further killings and enforced disappearances."

United Nations Secretary-General Antonio Guterres also expressed concern this week about the worsening situation.

Guterres called for an "immediate end to violence against civilians and to ensure unhindered humanitarian access," his spokesman said.

Many Catatumbo residents fled to Venezuela or the neighboring Norte Santander region of Colombia.

Adib Fletcher, senior regional director for Latin America and the Caribbean at aid group Project Hope, said displaced families - including mothers with young children - were arriving in droves in Norte Santander.

"Some families have fled their homes with only one or two luggage and are unsure when they will be able to return," Fletcher said in a statement on Wednesday.

"As people find shelter in overcrowded areas, we worry about disease outbreaks and increased pressure on local health systems."

Zilenia Pana, 48, fled the fighting with her children, ages 8 and 13, for the relative safety of Ocana, a town in northern Santander.

Seeing "bodies is sad, painful. It breaks your soul, your heart," Pana told AFP.

She said she just prayed the fighting would stop so she could go home with her children. "That's what we want. That's what we ask of these people," she said.