Three prominent Soviet officials had been meeting with Western reporters at the National Press Club for almost 90 minutes. The crowd was thinning and the questioning was waning when a hand went up in the back of the room.

"How do you see your role here, and do you think it's a public relations battle?" a reporter asked.

The grim faces of the Soviet experts thawed briefly and one broke into a smile.

"I wouldn't use military terms here," said Nikolai Shishlin, deputy chief of information for the Communist Party Central Committee, obviously making a joke of sorts about such bellicose phrases during peace talks. "I think that our task here . . . is to try to bring . . . elements of trust and mutual understanding in Soviet-American relations.

"And, of course," he added, "we'll applaud the participants in press conferences set out by the U.S. side if they would be moved and prompted by the same goals."

It was the kind of multilayered comment -- partly a straight answer and partly a gentle gibe at the other side -- that might be made by a U.S. official during this media war that will dominate the upcoming week. Whatever weapons may be eliminated because of the agreement between President Reagan and Soviet leader Mikhail Gorbachev, it is clear that both sides have dusted off their public relations arsenals.

Five days before Gorbachev's arrival Monday, Soviet officials, whose phone numbers are seldom available to Western reporters working in Moscow, began daily presummit encounters with the media here.

Not to be outmaneuvered, U.S. officials scheduled the grand opening of the summit press center at the Commerce Department auditorium this morning with a briefing for many of the 5,000 to 6,000 members of the worldwide media.

With dueling interviews last week -- Gorbachev on NBC Monday night and Reagan on four networks Thursday night -- the battle for the airwaves is also continuing at various levels down the line in both governments' bureaucracies.

U.S. officials are more adept at getting on American television, but the Soviets, who have brought about 20 briefers and 160 experts in various fields, have set up offices in the Madison Hotel to help match reporters with Soviet officials.

For most members of the media, who probably will see Reagan and Gorbachev only on television, briefings will provide the best source of their own information. Although the "daily feedings" -- as some reporters refer to the news conferences -- are similar in some ways, there are stark differences in style.

The Soviet briefing does not automatically begin, as does an American briefing, with a statement of the "ground rules." White House sessions usually start with the announcement that the briefing is "on background," which means that the briefer can be identified only as a "senior administration official." By contrast, the Soviets introduce themselves and set up hand-lettered nameplates to aid those unaccustomed to Russian spelling.

The Soviet method has prompted U.S. reporters to ask for a little more glasnost these days from the Reagan administration. At Thursday's White House briefing, Johanna Neuman of USA Today said: "I'd like to object, as a matter of principle, to having these briefings on background. The Soviets are briefing on the record."

"Hear, hear," other reporters shouted.

"Some of these {U.S.} briefers go on camera and say the same things they said on background," she added.

White House spokesman Marlin Fitzwater responded: "I appreciate your comments. They are very well taken. I'll take them into consideration."

"In other words, forget it, huh?" groused a reporter in response.

Alexander V. Lavrentiev, a Washington correspondent for the Soviet news agency Tass and a veteran of superpower briefings, said, "Sometimes I think the background briefings are held to attract attention to what they are saying. You know, if somebody says, 'You can't use this, can't attribute this to me,' you are naturally more interested in it."

For some journalists who covered the Soviet Union years ago, the sight of Soviet experts answering pointed questions from westerners has been a stunning change.

"The dialogue is so much more direct," said Hedrick Smith of The New York Times Magazine, a former Moscow correspondent. "There was far less circumlocution even than two years ago in Geneva."

Others emphasized the basic differences that remain between the two countries' media. "I didn't understand how the head of a news agency could be up there speaking for the Soviet Union," said Mark Nolan, a veteran radio reporter for the Associated Press. He was referring to Valentin Falin of the Novosti Press Agency.

"It serves to remind us that the Soviet press is different, part of the government," Nolan said.

Questions by representatives of small, offbeat newsletters, whose queries sometimes draw snickers or nonanswers at U.S. briefings, are treated as politely by the Soviets as are the reporters from the major newspapers and networks.

"Do you think they can tell the difference?" said Lars Erik Nelson, columnist for the New York Daily News. "From their point of view it's just one seamless web. We and they are just at different parts of the spectrum, and they can't really tell the crazies from the rest of us."

When yesterday's Soviet briefing seemed to be taken up mostly by the fringe media, some reporters from larger news organizations began whispering to the Soviets about who the questioners were and why they seemed to be yelling little speeches or making accusations that barely ended with a question mark.

Still, even the angriest of questions seem to lose steam as they are translated in monotonic or perhaps noncommittal Russian by young, fresh-faced Soviet interpreters who wear horn-rimmed glasses and navy blue suits. The translators are there because these briefings are considered official events, not because the high-level Soviets can't understand English -- most of them speak English, and even the American idiom, fluently.

After a briefing Thursday on the Soviet economy, during which the three briefers spoke only Russian, Cable News Network correspondent Gene Randall walked to the briefing table to talk to Shishlin.

"We understand that there has been a great deal of opposition to these reforms," Randall said in English.

"We have our liberals, our right wing, our right and left, too. I would not make too much of it. We will still go forward," Shishlin said, also in English.

By yesterday, after three Soviet briefings of more than 90 minutes each, some American journalists were beginning to make jokes about how it was time to go back to the era when these guys could only be seen in overcoats at the May Day parades.

As one Philadelphia reporter fled a Soviet briefing after an hour, he bellowed to those staying for more: "I believe I've enjoyed as much of this as I can stand."