BOGOTA, Colombia — Security forces in Colombia have killed one of its most-wanted drug fugitives, the alleged No. 2 leader of a ruthless criminal network that arose from disbanded right-wing paramilitary groups to become the nation’s largest drug-trafficking organization.

Gulf clan capo Roberto Vargas, best known by his alias “the hawk,” was slain in an operation by an elite commando unit near his base in the Gulf of Uraba region of northern Colombia. Authorities had offered a $165,000 bounty for him.

“This was one of our most-sought targets. We had been on his trail for a long time,” President Juan Manuel Santos said Friday at a news conference to discuss the operation.

Blu Radio reported that Vargas was killed at a home along with a dozen gunmen while watching a soccer match Thursday between Colombia and Venezuela.

As Colombia implements a peace deal with the nation’s largest rebel movement, it has been redirecting its security forces to combat criminal gangs that have aggressively stepped in to fill the void left by retreating guerrillas.

More than 1,500 members of Colombia’s security forces have been trailing the Gulf clan’s top leaders for over two years. During that time they have seized more than 100 metric tons of cocaine believed to belong to the group.

Vargas’ background — he had 22 arrest orders for crimes including murder, extortion and drug trafficking — mirrors Colombia’s bloody recent history and the sometimes blurred lines between criminal activity and political insurgence.

He is believed to have gotten his start as a gunman with the leftist Popular Liberation Army and then later switched sides and joined the rebels’ battlefield enemies, a right-wing paramilitary group. When that militia demobilized in 2006, he joined an emerging criminal band now led by Dairo Usuga, the country’s top fugitive, for whom the United States has offered a $5 million reward.

Santos said Vargas’ death and the recent arrest of dozens of Gulf clan members should serve as a wakeup call to Usuga so that he and his protectors surrender to face justice.

But some authorities in the turbulent Uraba region expressed concern that the Gulf clan could retaliate. Earlier this year the group carried out a rash of police killings to intimidate officers, in the style of the late drug lord Pablo Escobar.

The campaign against the Gulf clan comes at a time of flux in Colombia’s drug war.

Coca production in the country surged 18 percent last year to levels unseen in nearly two decades of U.S. eradication efforts, according to a White House report.

Authorities have stepped up their pursuit of drug traffickers even as they chase a goal of destroying 100,000 hectares of coca crops this year through a combination of manual eradication and voluntary crop-substitution agreements with farmers.