"Yes, this [ELN responsibility for the attack] is one the strongest versions," Penalosa said on Monday, adding that the similar attacks had taken place in 2016, and ELN had claimed responsibility for them.
The ELN wrote on Twitter that none of its groups had claimed responsibility for the explosion.
The blast occurred in the central part of the Colombian capital of Bogota, injuring 26 people, mostly police officers.
On February 8, the Colombian government and the ELN started peace talks, while the agreement to begin the dialogue was reached in mid-January.
ELN is the second largest guerrilla movement after the Revolutionary Armed Forces of Colombia (FARC), estimated to have between 1,500 and 3,000 fighters. The United States considers it a terrorist organization.
The peace talks with the FARC began in 2012 and the final peace agreement was signed at the end of 2016.
