The United States, Britain and France announced tonight that they are making "strong representations" to the Soviet Union to halt what Secretary of State George P. Shultz calls an unacceptable attempt by East Germany to restrict freedom of movement in divided Berlin.

While flying here today for the spring meeting of North Atlantic Treaty Organization foreign ministers, Shultz indicated to reporters on board his plane that the western powers are becoming concerned about East German attempts to require passports and other documents from western diplomats crossing between West and East Berlin.

U.S. officials said the East Germans were not attempting to apply these measures to American, French or British officials but were demanding that diplomats from other western countries show diplomatic passports before being allowed to enter East Berlin.

"What is happening is that countries other than the occupying powers are having difficulties moving across the sector line in Berlin," Shultz said. "We can't tolerate having a sector line converted into an international border."

Tonight, the "Berlin dinner" held at every NATO meeting by the foreign ministers of the United States, Britain and France, plus West Germany concluded with a statement saying: "The ministers of the three governments with special responsibility for Berlin will make strong representations to the Soviet Union in the context of quadripartite responsibility for the status of Berlin."

Since the end of World War II, the West has maintained that greater Berlin is under the ultimate authority of the four principal victors -- the United States, the Soviet Union, Britain and France.

A senior U.S. official said, "We are not dealing with the East Germans since we regard this as a Soviet controlled sector where East Germany has no competence," the official said.