Nick Clegg has attacked "unfounded" allegations by Argentina that the UK has deployed nuclear weapons near the Falkland Islands.
Speaking at a nuclear security summit in Seoul, South Korea, the deputy prime minister responded to accusations made by Argentina's foreign minister Hector Timerman.
"Before I turn to the issue at hand," Clegg said. "I’m afraid I’m duty bound to respond to the insinuations made by the Argentinian delegation of militarisation of the South Atlantic by the British government."
"These are unfounded, baseless insinuations. As I’m sure our colleague from Argentina knows the United Kingdom ratified the protocols to the treaty in 1969, the treaty referred to by President Pinera which guarantees a nuclear weapons-free zone covering Latin America and the Caribbean.
He added: "We have respected those obligations since 1969 and we will continue to do so."
Timerman told the summit on Tuesday that an "extra-regional power" had deployed a submarine "capable of carrying nuclear weapons" in the South Atlantic.
In February he also stated that his country had intelligence that a Royal Navy Vanguard class submarine had been sent to the area, and demanded to know whether it was carrying nuclear warheads.
"Thus far the UK refuses to say whether it is true or not," he said at the time. "Are there nuclear weapons or are there not?
He added: "The information Argentina has is that there are these nuclear weapons."
The Ministry of Defence has refused to either confirm or deny the deployment of a submarine with a spokesperson saying: "We do not comment on submarine deployments."
Tensions between Argentina and Britain have been simmering for months as the 30th anniversary of the Falklands War approaches.
The rhetoric from both London and Buenos Aires has died down in recent weeks, but the spat in Seoul is just the latest in a series of diplomatic shots.
Argentina reacted angrily to the recent deployment of the Royal Navy's most advanced destroyer HMS Dauntless (pictured below) to the region, as well as the decision to send Prince William to the Falklands in his capacity as a RAF search-and-rescue pilot.
Britain has condemned the decision by Argentina to ban Falkland Islands-flagged ships from docking at its ports, as well as its attempts to raise the issue of the territory's sovereignty at the United Nations.
Clegg also used his speech to disclose that the UK had been protecting its borders since 2001 with hi-tech equipment to detect illicit trafficking into the UK of radiological and nuclear material.
“We have been using cutting edge technology for over a decade to guard our borders against a nuclear terrorist threat. It is time to share that information so we can all raise our game," he said.
"Our groundbreaking new forensics lab will further enhance our ability to deal with nuclear and radioactive crimes and means terrorists have no place to hide.”