Human rights activists in Belarus say the authorities have detained dozens of people across Belarus on charges of insulting a government official or inciting social hatred following a shooting earlier this week in which an IT worker and a KGB officer died -- an incident that the U.S. envoy to Minsk said appears to confirm the regime of authoritarian leader Alyaksandr Lukashenka’s "disregard" for human rights.

The Minsk-based Vyasna human rights group said on September 30 that some 50 people were detained amid an intensifying crackdown on civil society, the political opposion, and independent media following last year’s disputed presidential election.

According to Vyasna, the detentions took place the previous day and “were probably connected with comments on social media about the deaths of [Andrey Zeltsar] and a KGB officer.”

The Belarusian Interior Ministry did not immediately comment on the reported detentions, which came after the Committee of State Security (KGB) said on September 28 that its officers shot dead a 31-year-old man and arrested his wife in a raid on their apartment in Minsk.

It gave no details on the man, saying only that he was a "terrorist" -- a term the KGB often uses to describe protesters and those voicing opposition to Lukashenka's regime.

The KGB also said the man had been killed after firing at security forces, leaving one officer dead. There has been no independent confirmation of the KGB statement, including whether the man had fired at security forces.

Earlier on September 30, U.S.-based software firm EPAM Systems confirmed reports that the man killed by Belarusian security forces was an employee of the company.

In a statement to Reuters, EPAM did not release any further details. It said it couldn't confirm media reports that the employee held U.S. citizenship.

Meanwhile, Julie Fisher, the U.S. ambassador to Belarus, said that Washington is seeking additional information on whether the "victim" is a U.S. citizen.

In a Facebook post, Fisher said the Minsk incident "appears to provide further evidence of the regime’s disregard for #humanrights and its willingness to utilize extreme methods to threaten perceived political opponents."

"The United States condemns these actions and the full range of politically motivated attacks against civil society, media, private companies, and political opponents," she wrote.

Belarus was engulfed by protests in 2020 after a presidential election in August -- which the opposition and West say was rigged -- gave Lukashenka a sixth consecutive term.

In response, the government has cracked down hard on the pro-democracy movement, arresting thousands of people and pushing most of the top opposition figures out of the country.

Prominent independent nongovernmental organizations such as the Belarusian Association of Journalists have been forcibly closed, while seven members of Vyasna have been jailed, pending trial on criminal charges.

The group said in its statement on September 30 that Belarusians "continue to be detained, searched, pressured, and subjected to other forms of pressure for their active civil position and dissatisfaction with the government's actions."

On September 29, the commander of the internal troops of the Interior Ministry, Mikalay Karpyankou, said the Minsk shoot-out would prompt new, and much harsher, tactics when dealing with situations where police are attempting to gain entry to residences.

"Now, the security forces will act in the following way: if the doors are not opened, they will be blown open and then stun grenades will be used, a dog will be sent in, and if the special forces don't see someone with raised hands, they will shoot to kill," he said on state television.

Lukashenka, who has run the country since 1994, has denied any fraud in the August 2020 vote and refuses to negotiate with the opposition on a political transition and new elections.

With reporting by Reuters