President Corazon Aquino will order the dismantling of the six U.S. military bases in the country unless U.S.-Philippine talks produce an agreement by January, an official said Thursday.

In a related development, the Aquino government handed out a 10-page pamphlet to the news media that sought to minimize the bases' political and economic importance.The pamphlet also said the installations spread disease and cause social problems.

In Washington, the State Department warned Americans in the Philippines of "a possible imminent terrorist bombing" by the communist New People's Army against U.S. government or other public facilities in Manila.

A brief statement attributed to spokeswoman Margaret Tutwiler said the danger was greatest "in the vicinity of Roxas Boulevard," where the U.S. Embassy is located and where talks on the future of the six U.S. military bases in the Philippines were being held.

American civilians said they were contacted by the embassy Thursday and advised of the alleged threat.

U.S. and Philippine officials began talks Tuesday on whether to allow Clark Air Base, the Subic Bay naval base and four smaller installations to remain after their lease expires in September 1991.

"If there is no treaty or arrangement, let's say by January . . . then we will most likely create a committee that will oversee the dismantling of the bases," said Rafael Alunan, spokesman for the Philippine panel.

Chief U.S. negotiator Richard Armitage said Tuesday that the days of a large American military presence in the Philippines were coming to an end and suggested the Filipino people vote on a continued presence at the end of the century. The United States maintains 40,000 troops, Defense Department civilians and military dependents at the six bases.

Aquino said on the eve of the talks that the time had come for an orderly withdrawal of the bases, the oldest and largest American overseas installations.