BOGOTA (Thomson Reuters Foundation) - Thousands of Colombians have fled their homes amid fresh clashes among armed rebels and a lockdown on transport and trade in the volatile northeast Catatumbo region, the Organization of American States (OAS) and aid agencies said on Wednesday.

The violence has uprooted at least 1,000 families in Catatumbo seeking to escape the crossfire in disputes over drug trafficking and territorial control along the border with Venezuela.

Aid groups and authorities have declared an “humanitarian emergency.”

Waging battles are the National Liberation Army (ELN) rebel group and the smaller Popular Liberation Army (EPL), also known as the crime gang “Los Pelusos”, in areas previously controlled by the Revolutionary Armed Forces of Colombia (FARC).

FARC demobilized last year following a 2016 peace deal, leaving the areas as flashpoints for fighting among crime gangs and rival rebel groups.

The OAS mission designed to support the peace process in Colombia said it was “deeply concerned” about what it called an “humanitarian emergency.”

It urged the government to protect civilians and for armed groups to cease fighting and respect human rights.

“In addition to murders, forced displacements and kidnappings, restrictions on the mobility and confinement of communities have arisen, who are intimidated by the actions of illegal structures,” it said in a statement.

The EPL, active in parts of the Norte de Santander province where Catatumbo is located, announced on Sunday a so-called armed strike, meaning an unofficial lockdown that restricts transport and business in some areas.

Residents say they received pamphlets about the lockdown, and local television footage showed a large red poster perched on a mountain road with details of the strike.

Shops and markets are closed, buses canceled, squares and roads emptied and some hospitals are shut, turning parts of Catatumbo into ghost towns.

Provincial governor of the Norte de Santander province, William Villamizar, declared a state of humanitarian emergency in Catatumbo on Monday to help displaced people receive aid.

Schools have been closed all week, affecting about 45,000 children and 2,000 teachers, according to the Norwegian Refugee Council.

“The communities in these regions should feel safe, and armed actors must respect the lives of civilians,” said Christian Visnes, its country director in Colombia.

“The de-escalation of conflict in Catatumbo cannot wait another day.”

The U.N. humanitarian agency OCHA has said violence by armed groups in the Catatumbo region since last month already has affected more than 20,000 Colombians, including some 2,500 people forced to flee their homes.

The government says it is addressing the problem and has sent more troops to Catatumbo.

Ecuador on Wednesday said it would no longer be a guarantor country at peace talks between the Colombian government and ELN rebels as long as the guerrillas wage attacks.

A new venue for the sometimes-fraught, 14-month-long talks has yet to be announced by the Colombian government.