American businesses urged their employes traveling abroad to be cautious in reaction to the slaying of an international businessman in France yesterday, but few companies are halting business trips.

"We've issued no directives about travel abroad," said a spokesman for Black & Decker Manufacturing Co. in Towson, Md. "We will encourage people to take common-sense precautions, but it's our intention to maintain continuity" by traveling to plants in other countries.

Kenneth Marston, regional director of the French subsidiary of Black & Decker, was shot and killed by an unknown gunman in Lyons. French authorities were skeptical about the claim of an anonymous caller that "a small Arab group" was responsible.

Representatives of companies such as General Electric Co., International Business Machines Corp. and American Express Co. said yesterday that, while they are urging employes living or traveling abroad to be cautious, they are not planning cutbacks in international travel.

"We are continuing international travel on a business-needs basis," said a spokesman for IBM. "We have tightened some security measures abroad."

Most large multinational firms provide their employes with advisories on where travel is considered safe, and more and more are leaving it to the discretion of the employe on whether to travel..

Of companies surveyed yesterday, only E. I. du Pont de Nemours & Co. of Wilmington, Del., has banned employe business travel to the Middle East and urged postponement of trips to Europe. That action, which was taken before Marston's death, resulted from the company's fears of terrorist activities, officials said..

"They're closing ranks, but nobody's breaking and running," said Eugene Mastrangelo, president of Risks International, a firm based in Alexandria that advises businesses on terrorism.

"They're sharing information and cooperating because they're all in the same boat," said Mastrangelo.