A Philadelphia pharmaceutical company, citing tampering threats involving at least four cities, warned consumers nationwide yesterday to stop using three popular over-the-counter capsules -- Contac, Dietac and Teldrin -- purchased since Saturday, and it urged stores to stop selling them.

In a statement, SmithKline Beckman Corp. said three of its capsule products were tampered with. "While no injuries have been reported," it said the company "is moving to halt all retail sales."

Food and Drug Administration spokesman Bruce Brown said the company decided voluntarily to issue a nationwide alert.

Authorities said the cities specifically cited in telephoned threats are Orlando, Fla., Houston, Chicago and St. Louis. But, Brown added, "Some of the calls said that tainted capsules had been delivered around the country."

As of last night, he said, no evidence of poison had been discovered in the products, and the agency had received no consumer complaints.

He said "no lethal and no toxic substances" such as cyanide and rat poison mentioned in the threats were found, but that other foreign substances were identified. The company initially reported discovering sugar and corn starch.

The Federal Bureau of Investigation said it is giving "highest priority" to investigating the incidents.

The full names of the three products are Contac cold capsules, Teldrin allergy relief capsules and Dietac appetite suppressant capsules.

The company statement said "several packages" of the products were found tampered with after anonymous telephone calls Wednesday and yesterday to the company, various police agencies and the news media.

According to the statement, the callers said "retail outlets in Orlando, Houston, Chicago and St. Louis were targeted to receive tampered products. The tampering incidents took place over the last four days, and the tampered products were discovered in the stores in Orlando and Houston."

"Several blister packs had been unsealed and the capsules broken into," it added. "Despite the geographic limits of the threat," it asked "all consumers who have purchased the three products since March 15 not to use them."

Sources close to the investigation indicated that many of the telephone threats apparently were made by a man who "expressed unspecified dissatisfaction with the company and with all capsule drug products but" did not seek money.

Brown said that the first telephone threats Wednesday mentioned only Orlando and Houston and that Chicago and St. Louis were added yesterday.

The FDA said any of the three products purchased since Saturday should be "set aside" out of children's reach until more information is available.

An ABC News spokesman said yesterday that two calls had been made Wednesday morning to the office of anchorman Peter Jennings by a man who identified himself as "Gary" and said "some people would be killed" by poisoned capsules in stores in Houston and Orlando.

The spokesman said ABC alerted authorities but did not report the incident until last night.

The incidents follow Johnson & Johnson's decision last month to discontinue making Tylenol capsules. That followed the death of a New York woman who took cyanide-tainted Extra Strength Tylenol.

At the time, the Proprietary Association, a trade group representing over-the-counter drug manufacturers, said the industry would continue to back use of capsules for other consumer products.