A Pakistani official denies British media reports after a package containing the radioactive metal was discovered last month.

Newspapers including The Sun, a tabloid, and the Guardian made the claim, as well as Sky News, a broadcaster.

“No information to this effect has been shared with us officially. We are confident that the reports are not factual,” Mumtaz Zahra Baloch, spokeswoman of Pakistan’s Ministry of Foreign Affairs, told Al Jazeera on Thursday.

However, another government official told Al Jazeera on the condition of anonymity that there is a sense of fear that the incident might affect Pakistan’s reputation “unjustifiably”.

Earlier this week, London’s Metropolitan Police force confirmed that after routine cargo screening, a package containing “a very small amount of contaminated material” was identified incoming to the UK. Counterterrorism police are investigating the incident.

The office of Prime Minister Rishi Sunak told Al Jazeera in a statement there is no threat to public safety. “We do not comment on live investigations. But operationally, we do not currently assess that this poses any threat to the public,” the office said.

According to reports, uranium was embedded into metal bars in a package that reached London via Muscat, on an Oman Air commercial flight.

Uranium is a rare radioactive metal commonly used as fuel for nuclear power, including in reactors, submarines, power plants and weapons.

An Islamabad-based security analyst, who requested anonymity due to the sensitivity of the matter, said if the investigation finds the package did originate from Pakistan, it would indicate gross negligence in the country.

“The detection of metal bars contaminated with ‘small quantity’ of uranium at London’s Heathrow airport is very concerning. If the port of origin of these metal bars is correct, that means the radioactive bars managed to pass through multiple scanning and security checks at a Pakistani airport,” the analyst said.

For a detailed investigation, the sender’s identity can easily be traced if UK authorities share relevant information with the Pakistani side.

The Sun, which first reported the story, claimed the package was “destined for Iranian nationals in [the] United Kingdom”.

Richard Smith, head of the Metropolitan Police’s Counter Terrorism Command, said on Wednesday: “An element of cargo was identified that was emitting a radioactive signal.”

“The amount of material we’re talking about was very small, and there was no threat to public health or public safety identified.”