Bogota, Jan 18 (efe-epa).- Colombia's government said Friday that the National Liberation Army (ELN) leftist guerrilla group was behind a car bombing at a police academy in this capital that left at least 21 dead - including the attacker - and 68 injured.

"A terrorist attack by the ELN took these lives in one fell swoop," Defense Minister Guillermo Botero said in a press conference at Casa de Nariño, the presidential palace.

He added that 20 police cadets between the ages of 17 and 22 were killed in the attack, which was carried out on Thursday morning.

The vehicle that burst through the gates and exploded at the Francisco de Paula Santander police cadet training academy in southern Bogota was laden with 80 kilos (175 pounds) of the explosive pentolite.

The minister confirmed that the driver of the vehicle used in the attack was a 56-year-old man - Jose Aldemar Rojas Rodriguez - who had lost his right hand sometime between 2008 and 2010 while handling explosives.

He had been a member of an ELN front located in the northeastern province of Arauca, near the Venezuelan border, since 1994 and had carried out numerous attacks on oil infrastructure in that region, Botero added.

Attorney General Nestor Humberto Martinez said at the same press conference that Colombian authorities early Friday arrested a suspect in the attack identified as Ricardo Andres Carvajal.

In a statement Thursday, Colombian President Ivan Duque vowed to punish those responsible for the car bombing.

"We Colombians have never submitted to terrorism and this will not be the exception. They won't bend us. We won't give way a single step to those who miserably attack society," Duque said.

The administration of Duque's predecessor, Juan Manuel Santos, launched talks with the ELN in February 2017 in a bid to reach a peace deal similar to one it finalized with the larger Revolutionary Armed Forces of Colombia (FARC) guerrilla group in 2016.

But those talks have been on hold since the sixth round of negotiations concluded on Aug. 1 in Cuba.

Duque, who took office six days later, has said that for peace talks to resume the ELN would have to give up its criminal activities, especially kidnapping, and free all of its captives.