British Prime Minister David Cameron visited Oman on Friday as Britain's defence giant BAE Systems announced a 2.5-billion pounds ($4.1-billion) deal to supply fighter planes and trainer jets to the sultanate.

Cameron met Sultan Sultan Qaboos to discuss "ongoing cooperation between both countries in several fields in light of their good relations and the mutual interests of their friendly people," Oman news agency ONA reported.

On Thursday, the prime minister paid a pre-Christmas visit to British troops serving in Afghanistan.

On his way home as he arrived in Muscat for a brief visit, BAE Systems announced in London that it has sealed a multi-billion dollar fighter jets deal with Muscat.

"BAE Systems and the government of the Sultanate of Oman have entered into a contract for the supply of Typhoon and Hawk Advanced Jet Trainer aircraft to the Royal Air Force of Oman," the London-listed company said in a statement.

"The contract, valued at approximately 2.5 billion pounds, provides for the delivery of 12 Typhoon and 8 Hawk aircraft starting in 2017."

ONA later said that "this deal comes within the framework of Sultan Qaboos's concern ... in developing the capabilities and potential of the Omani Air Force."

Oman will become the seventh nation in the world, and only the second in the Middle East after Saudi Arabia, to operate the Eurofighter Typhoon.

"We believe that Oman has now added the most advanced fighter jet and proven training aircraft, available in the world, to its military portfolio," said Guy Griffiths, group managing director for BAE Systems' international business.

Oman has historically close relations with Britain and is the only Arab state in the Gulf that also has warm ties with neighbouring Iran, enabling it to become a key mediator between Tehran and the West.

On Tuesday, Oman said it had mediated the repatriation from Britain of former Iranian diplomat Nostratollah Tajik, who won a British court ruling against his extradition to the US where he is wanted for allegedly smuggling arms.