Colombian President Juan Manuel Santos on Sunday said his government would strive to negotiate a second ceasefire agreement with the National Liberation Army (ELN) guerrilla group.

In response to a United Nations call for continued dialogue between the two warring sides, he said he instructed Gustavo Bell, the head government negotiator in peace talks with the rebels, to return to Quito, Ecuador, where the talks are being held.

“In keeping with the call by the United Nations (UN), Gustavo Bell will travel to Quito to explore the possibility of a new ceasefire that will allow us to continue to negotiate for peace with the ELN,” Santos tweeted.

On Saturday, the UN urged both sides not to abandon efforts to put an end to five decades of fighting.

The ELN also expressed its willingness to continue the talks, issuing a statement saying “we agree to take part in a meeting between the heads of the delegations … to examine the prompt start of the fifth round of talks to discuss all pending matters.”

A bilateral ceasefire, which took effect Oct. 1, 2017 as a way to promote good will during the talks, expired on Jan. 9, after which the ELN immediately resumed its attacks against state targets, especially oil pipelines.

The attacks led Santos to recall Bell to Bogota for consultation as to what steps the government should take next.