The United States will provide an estimated $125 million in disaster assistance to Jamaica to aid recovery efforts from some $1 billion in damage inflicted by Hurricane Gilbert, the White House announced Monday.

President Reagan promised the disaster aide during a brief Oval Office meeting with Jamaican Prime Minister Edward Seaga, whose country suffered extensive damage from the hurricane last month, the White House said.The $125 million in promised long-term assistance includes $3.2 million in immediate relief aid, as well as development assistance and economic support funds for fiscal years 1988 and 1989.