"In view of the position publicly assumed (by the ELN)... we have decided to suspend the legal effects of the decree," Interior Minister Alfonso Prada told reporters in Bogota.

Colombia's President Gustavo Petro announced on New Year's Eve that a truce had been agreed with the country's five largest armed groups, including the National Liberation Army (ELN), from January 1 to June 30.

The government subsequently said the truce, hailed by the international community, would be monitored by the United Nations, Colombia's human rights ombudsman and the Catholic Church.

But on Tuesday, the ELN said it had "not discussed any bilateral ceasefire with the Gustavo Petro government, therefore no such agreement exists."

This prompted the government Tuesday to concede that a proposed ceasefire decree had yet been signed.

Negotiations between the government and the ELN, the country's last recognized rebel group, have been under way since November.

A first round of peace talks since Petro came to power in August concluded in Caracas, Venezuela on December 12 without a truce being agreed.

Another round of talks is due to take place in Mexico, although no date has been set.

Prada said the issue of a ceasefire will be taken up again in Mexico.