Britain's Deputy Prime Minister Nick Clegg on Tuesday angrily dismissed charges from Argentina that London had sent a nuclear-armed submarine to the South Atlantic as "baseless".

Clegg was speaking at a summit on nuclear security in South Korea after Argentina's Foreign Minister Hector Timerman challenged Britain to confirm it had no nuclear arms in the seas around the Falkland Islands.

In an unusually frank clash in front of more than 50 world leaders at the summit in Seoul, Clegg said he felt "duty bound" to respond, saying: "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... which guarantees a nuclear weapons-free zone covering Latin America and the Caribbean.

"We have respected those obligations since 1969 and we will continue to do so," Clegg said, in quotes released by his office.

Timerman had said earlier: "Argentina is demanding that the outside power (Britain) which has recently sent a submarine capable of transporting a nuclear arsenal to patrol in the South Atlantic to confirm the absence of nuclear arms in the region."

He called the attention of the summit participants to Britain's actions, claiming London had "sent a nuclear submarine to an area whose sovereignty is disputed by the United Nations... and refuses at the same time to confirm that this action would not introduce nuclear weapons in a nuclear-free zone."

A newspaper reported that Britain had deployed a nuclear-powered -- but conventionally armed -- Trafalgar class submarine to the seas around the Falklands.

The Ministry of Defence refused to confirm or deny this, as it never comments on submarine deployments.

The clash in Seoul was the latest episode in the increasing tensions between Argentina and Britain ahead of the 30th anniversary of the start of the Falklands War in 1982.

The barren archipelago has been bitterly disputed between the two countries.

On April 2, 1982, the then-ruling junta in Argentina invaded the Falklands, sparking a 74-day war with Britain which cost the lives of 649 Argentine and 255 British troops.

Britain has held the Falklands since 1833, but Buenos Aires claims they are occupied Argentine territory.