text: Daniel Filmus, Argentina's minister for the islands - called the Malvinas locally - announced the case in London.
  The companies involved are Falkland Oil and Gas, Premier Oil, Rockhopper, Edison International and Noble Energy.
  Mr Filmus told the BBC the companies were "performing illegal acts by entering Argentine territory".
  He added: "I want to make it clear for the directors of these companies and for British public opinion that Argentina will use the full force of the law - both national and international law - to prevent these countries from taking the riches which belong to 40 million Argentine citizens.
  "Argentina has extradition treaties around the world and we intend to use them."
  He added that the area being drilled was "as much ours as the centre of Buenos Aires. Neither the UK nor any other country would allow anyone to enter their territory and take away their riches."
  In response, UK Foreign Secretary Philip Hammond accused the Argentines of "outrageous bullying".
  He said the islanders had a "perfect right to develop their own economic resources and Argentina needs to stop this kind of behaviour and start acting like a responsible member of the international community".
  The Falklands Islands government also said the Argentines had no case.
  "We have the right to develop our economy, including the hydrocarbons industry, and we are exercising that right," it said.
  "It is worth remembering that it was the government of Argentina who walked away from working with the Falkland Islands on the development of a hydrocarbons industry some years ago.
  "Argentine domestic law does not apply to the Falkland Islands and this latest action is clearly another attempt by Argentina to try to block economic growth in the Falkland Islands."
  Analysts suggested Argentina would have little joy in the courts.
  "The Argentines will lose," Malcolm Bracken at Redmayne Bentley told the BBC. "They have no jurisdiction - the UN settled the matter in 1982."
  In fact, he said the country's current position would prove counterproductive.
  "All they're doing is handing any possible benefit that Argentina may have had from the oil boom in the south Atlantic to Chile.
  "There'd be an awful lot of logistic support needed for drilling that simply isn't available in the Falklands. They'd need a port somewhere and that's likely to be near Chile rather than Argentina, so they're cutting their own nose off to spite their face."
  Earlier this month, Argentine foreign ministry officials said they would prosecute oil companies operating near the Falkland Islands. The officials said companies active there were operating illegally in Argentine territory.
  This came after the three British oil companies announced new oil and gas finds north of the islands, and as Argentina marked the 33rd anniversary of the war with the UK over the islands.
  Tensions between the UK and Argentina were already running high after the UK announced it would spend Â£280m over the next 10 years on improving defences on the islands.
target: Argentina has begun legal proceedings against three British and two US companies for drilling oil near the Falkland Islands.