Families on Colombia's border with Venezuela have been displaced by illegal groups trying to fill the vacuum left by the departure of Farc rebels, the UN says.
Officials said 96 families in the northern region of Norte de Santander had fled their homes.
Some crossed the border into Venezuela and others went to refuges in local towns.
The UN said tension was high and they feared more families could flee.
According to the UN, various groups operate or have operated in the region: the Farc, Colombia's second largest guerrilla group, the ELN, and criminal and ex-paramilitary groups.
Norte de Santander has emerged as the country's main hub for coca cultivation.
Last week, peasant farmer organisations in the region, around Catatumbo, blocked the demobilisation of Farc units saying that their departure would leave them unprotected as the paramilitary groups gathered nearby.
There have also been reports by local communities of an increased presence of criminal groups in at least three other departments: Antioquia, Uraba and Choco.
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The Farc has largely left towns and rural areas it occupied and most of the fighters have gathered in 26 concentration zones under the watch of a multinational commission.
The Colombian military have moved into some territories in Tolima and Huila departments but, according to the government's Peace and Reconciliation Foundation, it is proving difficult to take over in more isolated regions because of the problems of terrain and lack of access.
The Farc is expected to hand over its arms by the end of May.
It has agreed to co-operate with investigations into drug trafficking and war crimes.
The armed conflict in Colombia has resulted in more than 220,00 deaths and 40,000 people missing over the past 50 years.
All sides have been accused of war crimes including massacres, torture and rape.
More than six million people have been displaced - the second highest number in the world after Syria.
And 11,000 people have been killed or maimed by land mines - a causality rate second only to Afghanistan.