Reuters quoted sources as saying that the phones of at least 9 employees of the US State Department were hacked using spyware produced by the Israeli NSO Group.
And the agency reported - quoting the sources it described as insider - that the hack targeted American employees who are in Uganda or who specialize in issues related to East Africa.
Reuters quoted the Israeli group, denying that there was evidence that its programs were used in that hack, and announced that it had canceled the relevant accounts, and that it would investigate the matter.
For its part, the US State Department said in a statement to Al Jazeera that it could not confirm that officials' phones had been hacked, but added that it was constantly taking steps to ensure that information was protected.
American concern
In the same context, a spokesman for the US National Security Council told Al Jazeera that he could not confirm the news of the hacking of the phones of US State Department employees.
However, the spokesman expressed the US administration's concern about the danger of spyware programs produced by the "NSO Group" to the security of American employees.
During the past months, the Israeli group - which produced the famous Pegasus spy program - faced a storm of criticism and pressure, after press reports revealed that its programs were used to spy on 14 heads of state and hundreds of journalists, activists, company managers and government officials around the world.
On November 3, the US Department of Commerce announced the inclusion of "NSO" in a blacklist as a national security threat, which came as a big surprise.
In its decision, the US Commerce Department said that the Israeli company had sold spyware to "tyrannical" foreign governments that it used to target government officials, journalists, dissidents and others.