A federal judge in Alexandria ruled yesterday that U.S. espionage laws cover acts committed outside American territory and are applicable to noncitizens.

The ruling by District Court Judge Albert V. Bryan Jr. clears the way for the trial of a Ghanaian national accused of espionage acts that, for the most part, allegedly were committed in his West African country.

"The nature of espionage is that it can be conducted anywhere and is often conducted anywhere," said Bryan as he rejected Michael A. Soussoudis' request for a dismissal of an indictment charging he secured secret information from a CIA employe in Africa.

"The fact that he was operating as a good citizen of Ghana is simply irrelevant if he was damaging the United States in the process," the judge said.

Soussoudis, a first cousin of Ghana's leader, Flight Lt. Jerry Rawlings, is to go on trial Oct. 15 on charges of espionage, conspiracy to commit espionage, receiving classified information and conspiracy to receive classified information.

Yesterday's hearing also disclosed that the government has identified other participants in the alleged espionage conspiracy.

Their names were not revealed and are being held under seal because of a protective order granted for national security reasons.

Soussoudis' indictment charges that while he was dating former CIA employe Sharon Scranage he allegedly sought and received classified CIA information from her. The information allegedly included the identities of five CIA employes and 11 Ghanians supplying information to the agency.

He was arrested at a Springfield motel where he was planning to meet Scranage, who lives in Virginia's rural Northern Neck.

Scranage, who worked for the CIA in Ghana from May 1983 to May 1985, has pleaded guilty in Alexandria to three counts of disclosing classified information to Soussoudis and will appear as a witness against him.

Attorneys for Soussoudis yesterday argued that U.S. courts had "no right and no power" to try Soussoudis for acts in Ghana.

Citing a "protective principle" of international law, one of the lawyers argued a country cannot prosecute an individual for acts outside its territory unless they are crimes "directed at the integrity of the U.S."

"Everything that was done," said Washington lawyer Plato Cacheris, "was directed at the peace and quiet of the nation of Ghana, not offensive acts against the U.S."

Bryan disagreed, saying the indictment "comes well within the protective principle."

Drawing Cacheris' attention to a charge accusing Soussoudis of obtaining information from a classified CIA cable, he asked: "You don't think that the revelation of that . . . is detrimental to the interests of the United States?"

Cacheris noted that the information Soussoudis allegedly received concerned plans for a coup by dissidents in Ghana.

"Certainly every country has the right to protect itself against such attempts and to be punished for that is ludicrous," he said.

"It was in no manner, way, shape or form aggression against the United States."

Bryan also held that Soussoudis' status in the United States as a permanent resident alien allowed grounds for prosecuting him. In any event, Bryan said, "I think this act does extend to espionage . . . by both citizens and noncitizens."

The ruling could assist government prosecutors seeking tougher court action against espionage. The government has sought only once before to prosecute a foreigner for espionage based on actions occurring outside the United States. In that case East German Alfred Zehe pleaded guilty earlier this year to espionage. He was traded to the Soviet bloc in a spy swap.