With the two companies facing possible criminal charges in Venezuela and a U.S. government investigation, Firestone asked Venezuelan dealers to return some unsold tires, but rejected appeals from the world's No. 2 auto maker to replace all its tires made in Venezuela.

``At this time we are not considering a voluntary recall of tires from the Venezuelan market,'' said Firestone, a unit of Japan's Bridgestone Corp., which accounts for almost half the tire market in the South American country of 24 million people.

Hector Rodriguez, purchasing manager for Ford in Venezuela, said a company investigation found 14 percent of Firestone's 15-inch tires, fitted as standard on Ford's 4x2 Explorer SUV, showed signs of the tread separating from the tire.

``This is a number almost 1,000 times higher than in the United States,'' Rodriguez told a news conference in Caracas.

Ford officials said they had known about problems with Firestone tires in Venezuela since 1998, but only began recalling them in May 2000 as they had expected Bridgestone to take action.

The problem with the Venezuelan tires, made at Bridgestone's plant in the central northern industrial city Valencia, is the latest snag in relations between the two companies since Firestone recalled 6.5 million 15-inch ATX, ATX II and Wilderness tires in the United States this month.

DUBBED ``ASSASSIN TIRES''

The Venezuelan Firestone tires have reportedly been cited in as many as 400 accidents involving 100 deaths. Venezuelan media have dubbed the Firestones ``assassin tires.''

Ford vice-president of communications Jason Vines, told a conference call: ``We are confident this is a manufacturing defect in Venezuela ... as more than half of the tires we have analysed show they were not built to Firestone's own engineering drawings.''

Ford officials in the United States and Venezuela have urged Firestone to replace all its Venezuelan tires, not just those covered by a Ford programme to refit all Explorers in Venezuela with Goodyear Tire and Rubber Co. tires.

``To be quite honest, Firestone tires had lost good grace in Venezuela and we decided to go with Goodyear,'' Vines said.

Ford Motor Venezuela President Enmanuel Cassingena said the Detroit-based company had already replaced tires on 60 percent of the 28,000 Ford Explorers in Venezuela and would refit the remainder in coming weeks at a total cost of $15 million.

Venezuela's government consumer protection agency, Indecu, has said it could recommend criminal charges against Ford and Firestone for misleading consumers about their products.

A court case in the South American nation would be a serious blow for the companies even as the U.S. government investigates some 100 accidents and 62 deaths linked to Firestone tires, most on Ford's Explorer, the most popular SUV in the United States.

Vines said Indecu had agreed to a create a technical commission of international and Venezuelan experts to examine the tires.

SHARES SINK

Bridgestone shares fell 4.5 percent in Tokyo to 1526 yen on investor concerns about a possible broadening of its recall into Venezuela and a new class action suit in Chicago.

Ford slipped 3/4 to $25-3/8 on the New York Stock Exchange.

The company's shares were hurt by a downgrade from Dresdner Kleinwort Benson equity analyst David Garrity, who removed his buy recommendation on the stock based on the recall.

``Ford's credibility with U.S. consumers, legislators and regulators may suffer,'' he wrote, in the first downgrade on Ford's stock since the recall began. ``The whole issue is, what did Ford know when?''

Explorers produced at Ford's Venezuelan plant are exported to Colombia and Ecuador. Ford has extended its recall to other Latin American countries, such as Argentina and Mexico, where it expects to replace around 100,000 tires, mainly on its Explorer models.

Firestone has accepted Indecu's findings that they mislabeled a number of tires in Venezuela, which did not possess a third protective layer of nylon to strengthen the tire's tread as stated on the label.

``This unintentional error did not affect the quality, performance and the safety of the products supplied to Ford,'' Firestone said in a letter to Indecu. ``We have fully corrected this situation.''