US affirms it's supplying Britain

The Reagan administration acknowledged that the United States is providing missiles and other weapons to Britain for use in the Falklands Islands conflict. The provision includes missiles, bombs, rockets, and ammunition.

The acknowledgment came as Latin American foreign ministers prepared to call on the US to stop helping the British forces and as Argentine President Leopoldo Galtieri told President Reagan his call for closer relations with Argentina was ''incomprehensible.'' The administration has been reluctant to discuss military materiel support for Britain because of damage to Washington's relations in Latin America.

The US assistance to Britain, a longtime ally, runs counter to action expected from members of the Organization of American States, which are signatories of the hemispheric mutual defense treaty called the Rio Pact.

The cost to Britain of the Falklands war, including the weapons Washington will supply, has risen to an estimated $1.8 billion, but this is officially regarded as manageable and within present budgetary limits.

This is four times the initial estimate for dispatching the task force, but only a long and intensified war to recapture and retain control of the Falklands from Argentine forces would blow the government off its present economic course and delay its plans to reduce taxes, senior officials said Thursday.