Two low-impact bombs that rattled nerves in the Colombian capital of Bogota on Thursday were likely placed by the rebel group known as National Liberation Army, or ELN, said Colombian President Juan Manuel Santos.
Santos left the Pacific Alliance Summit with other regional leaders in Peru earlier than planned to return to Colombia and address the bombings, which occurred at 3:45 pm at two pension fund offices in the Colombian capital. Ten people were injured.
"All the evidence until now points in the direction [of the ELN]," Santos said in a televised statement on Friday. He said the possible aim of the explosives was to "put pressure" on the peace process.
Colombia's government is currently involved in delicate peace negotiations with the Revolutionary Armed Forces of Colombia, or FARC, to end the 51-year internal conflict.
The ELN, which marks its 51-year anniversary on Saturday, is Colombia's second largest rebel group. The group is not involved in the peace talks in Havana, Cuba, though they have sought dialogues with the government on their own. A joint statement was released last June confirming exploratory talks between the government and the ELN, though these haven't yet been formalized.
The ELN has not claimed responsibility for the Thursday attacks.
The Bogota explosives were reminiscent of a similar string of bombings earlier this year that remain unexplained.
Speaking to local radio on Friday morning, Interior Minister Juan Fernando Cristo, refused to rule out extreme-right groups as possible culprits, saying that "we cannot rush to conclusions."
In a communique, the FARC suggested far-right groups were behind the Thursday attacks. The rebels ruled themselves out.
"We will continue fighting terrorism as we have been, with the constitution in one hand and a military offensive in the other," President Santos said Thursday night from Peru.
Police are offering 100 million Colombian pesos (approximately $48,000) for any information on the attacks.
Follow Joe Parkin Daniels on Twitter @joeparkdan.