British Deputy Prime Minister David Lammy said he told U.S. Vice President JD Vance that he was "wrong" to link the murder of British student Henry Nowak to immigration, following comments that reignited debate around the high-profile case.
Lammy said he challenged Vance during a phone call on Saturday after the vice president argued that Nowak's death reflected the consequences of what he described as the "mass invasion of migrants."
The dispute comes amid continuing scrutiny of police actions surrounding the killing and growing political tensions over how the case is being discussed.
Nowak, 18, was fatally stabbed in Southampton in December last year by Vickrum Digwa, a British man born in the United Kingdom.
Digwa falsely claimed he had been racially abused and acted in self-defense before later being convicted of murder and sentenced to life imprisonment with a minimum term of 21 years.
Bodycam footage showed police handcuffing Nowak as he lay dying after officers initially accepted Digwa's account of events.
The case has prompted an investigation by the Independent Office for Police Conduct into Hampshire Police's response.
Hampshire Police has since apologized for handcuffing and arresting Nowak.
The killing also sparked protests in Southampton, with demonstrations escalating into violence following Digwa's sentencing.
Lammy said he used his conversation with Vance to emphasize that the case was unrelated to migration.
He said the killer was British and that "This has got nothing to do with mass migration."
Despite describing the exchange as robust, Lammy said the discussion remained agreeable and reflected their longstanding personal relationship.
Downing Street also criticized attempts to inflame divisions, warning against efforts to interfere in Britain's democracy or stir unrest.
The case has become a focal point in wider debates about policing, race and public policy.
Reform UK figures have argued that policing guidance and anti-racism policies contributed to failures in the handling of the incident, while Lammy rejected claims that modern British policing remains institutionally racist.
Throughout the controversy, Nowak's family has urged restraint.
His father, Mark Nowak, said he did not want his son's death to be used to create "further division, hatred or tension."