Slavisa Krunic was ambushed late on April 22 in his car near his family's home north of Banja Luka, the capital of Bosnia-Herzegovina’s ethnic-Serbian entity Republika Srpska, reports said.

A witness to the shooting told RFE/RL that he heard a burst of gunfire and what appeared to be return fire in the town of Glamocani, about 15 kilometers north of Banja Luka.

“Police acted pretty quickly,” the witness said. “One patrol came really quickly, and two more units came shortly thereafter."

Banja Luka news portal Nezavisne Noviny reported that Krunic succumbed to his injuries after being hospitalized.

His bodyguard and one of the attackers were also killed in the shoot-out, reports said.

The suspected attacker who was killed, named as Zeljko Kovacevic, was reportedly a career criminal who served 11 years in prison for theft and burglary.

Police told RFE/RL that several people believed to be connected to the killing have been arrested in other areas of Republika Srpska.

A statement by the Republika Srpska Interior Ministry said two people had been arrested on suspicion of aggravated murder and attempted murder, identifying them only by the initials E.B. and M.G.

Police said a warrant has been issued for another suspected attacker, identified as B.D., and that a search is currently under way for him.

The U.S. Embassy in Sarajevo said on Twitter that it was “shocked by the brutal assassination of Slavisa Krunic, and express our condolences to his family, colleagues…”

“We expect the relevant authorities to take the necessary steps to investigate this crime and hold accountable those responsible,” it added.

The attackers were armed with automatic weapons, media reported. The motive was not clear.

In a recent interview with Bosnian television, Krunic criticized the ruling Bosnian Serb nationalist party and Milorad Dodik, its hard-line leader who has advocated for Republika Srpska to break away from Bosnia-Herzegovina.

Krunic accused Dodik of stoking ethnic tensions in the country as distraction from alleged corrupt activities.

"We are on the side of the forces that want to build this country and not to destroy it," Krunic said in the interview.

Krunic claimed he had been pressured to sell his company because he had hired ethnic Croatians and Muslim Bosniaks along with Serbs.

He said he was a Serb, but also a Bosnian because he was born in the country, as was his child.

Since the end of a 1992-95 war, Bosnia has consisted of two separate entities -- the Muslim-Croat Federation and the ethnic Serb-dominated Republika Srpska. Each has its own government, and the two are linked by weak central institutions.

Bosnian Security Minister Dragan Mektic, another vocal critic of Dodik and a member of a Bosnian Serb opposition party, tweeted that Krunic's killing had the "signature" of the authorities without specifying which authorities he had in mind.

Krunic owned several businesses, including a security company, an IT services firm, and a chain of bakeries.

A few years ago, Krunic publicly complained that he was under pressure from "someone [seen] every day on the political scene" to sell his businesses.

Corruption and crime are major problems in Bosnia.

Global watchdog Transparency International ranked Bosnia among the worst countries in Europe on its corruption perception index in 2018.

With reporting by AP and dpa