Updated

Colombia's second-largest rebel group says it was behind a bombing this month that killed a police officer in the capital.

The explosion near Bogota's bullring injured more than 20 riot police and shocked residents unaccustomed to political violence in recent years.

The National Liberation Army said in a Monday statement that a bilateral cease-fire must be declared to avoid any future attacks and give space to recently launched peace talks.

The group known as the ELN and the government recently entered talks aimed at ending decades of armed conflict after officials reached a deal last year with the much larger Revolutionary Armed Forces of Colombia.

Opposition members have used the attack to call on the government to break off discussions with the ELN.