Stung by recent press reports accusing bar owners here of discrimination against U.S. soldiers, Lord Mayor Willi Reiland recently led a group of government officials, GIs and reporters on an evening visit to several nightspots around town.

The aim was to demonstrate that the accounts of soldiers being snubbed were exaggerated and that they give an inaccurate picture of the relationship between this city of 58,000 and its 4,300 American troops.

Everyone was admitted and everyone was served at a pizzeria, a punk rock club and a posh discotheque. It hardly could have been otherwise with the mayor and a member of parliament present, along with a television camera team to record the event.

But it was otherwise when they had gone. "It is a problem," Ray Nez, the doorman at the Tilbury disco, acknowledged to a reporter who returned that same evening without the official entourage.

Running through the list of reasons for which his club owner and a number of establishments throughout West Germany keep Americans out -- they don't dress right, they get drunk, they turn rowdy, they can't speak German -- Nez concluded: "They stick out like a sore thumb."

"I'm not trying to put down Americans, because I was one myself," said the Philippine-born doorman, a former San Francisco resident who served a tour with the U.S. Army here before deciding to stay. "But we do claim the right to choose who our guests will be. This is not a train station."

His remarks have been echoed by German club owners who have been quoted in a spate of recent press reports about the problem. In a national television news broadcast here recently, Dieter Stelzner, owner of the Domizil discotheque in the Bavarian town of Amberg, explained his reason for shunning Americans:

"I have invested a lot of money. I regard the disco as my existence, and that's why I have to be sure that I keep quite a standard. We have a club here, and occasionally we let Americans come in, but they do not fit.

"Even if Americans, who after three weeks of a maneuver at the border with Czechoslovakia, want to let off steam and want to amuse themselves, I don't want the reputation of being an 'Ami' American bar," he said.

Friction between American soldiers and the towns they are based in is a problem as old as this Federal Republic. But anti-Americanism and a resurgence of German xenophobia are topics of interest and debate.

Army officials report that the number of German bars, clubs and discotheques that practice discrimination has fluctuated over the years and is in fact lower now than in some past years.

But the sense that something is worse has been encouraged by several occurrences. These include a number of highly publicized press reports lately about discrimination and one tragically violent case involving the killing of two GIs.

Adding to U.S.-West German strains over the subject was a news story in June quoting an unnamed Pentagon official at a conference in Racine, Wis., as saying some allies, notably West Germany, want a decrease in the number of black soldiers stationed in Europe. The West German Defense Ministry has denied that any such request was made.

West German politicians, including Chancellor Helmut Schmidt, have voiced fresh concern about the discrimination problem and a renewed commitment to fight it.

Pfc. Robert Tyson, 23, a black who is based here, said he learned quickly which establishments did not want him inside. He said he was told he was unwelcome in a pizzeria shortly after his arrival in May during a tour of the city with his Army "sponsor," a noncommissioned officer.

Chuck Kennedy, 27, a white lieutenant, was also part of the entourage. He said discrimination against GIs was not just a problem for blacks.

"I've been turned away, too," he stated. "They can tell by my haircut or my clothes that I'm a soldier or American. They will say it's a private club or no white pants are allowed or no jeans. Sometimes I've stood there and watched Germans with white pants or jeans be let in."

In recent weeks, The Stars and Stripes, the daily paper that describes itself as the authorized but unofficial publication of U.S. forces overseas, has published a series of reports describing allegations of prejudice, snubs and insults against American soldiers and generally outlining the discrimination record in various West German cities.

A German paper, Welt am Sonntag, in June sent a reporter with two black GIs to record the verbal abuse and closed doors they ran into here in several establishments. The headline, picking up on a quote by one of the soldiers involved, read: "I'm supposed to die for them but they won't give me a beer."

The situation took a tragic twist in June when a West German neo-Nazi on a rampage shot and killed two black Americans and an Egyptian at a disco in Nuremberg frequented by U.S. soldiers.

When Newsweek magazine's international edition ran a story in May on antagonism against U.S. soldiers under the headline, "The American Outcasts," Schmidt asked Gen. Frederick Kroesen, commander of the U.S. Army in Europe, to comment.

The general's reply affirmed that "in recent years the spirit of U.S.-West German friendship has been marred by small numbers of public establishments where American soldiers are denied access or service." Kroesen said the number of such places had been as high as 175 in recent times, and the Army is aware of 110 establishments that discriminate in some way.

Keeping an exact count, however, is complicated by what Army officials say is the tendency of many places to be sporadic in their discrimination.

"Although few in number, these establishments are conspicuous in a local setting," Kroesen wrote. "Discrimination is most pronounced where soldier concentration is heaviest and more frequently experienced by black soldiers."

At the Tilbury disco here, doorman Nez, whose perspective on the problem is unusual since he faced it first as a GI, said the shutting out of Americans may have less to do with race than with clashing U.S. and German cultures. "A lot of these young guys think they own the place," he said. "You know, 'We won the war,' and all that. They forget they're not in the States, that it's another culture, another mentality."

Under the glare of publicity, all the troublesome spots here -- Mayor Reiland put the number at 11 out of 372 establishments -- have been warned again. But local officials admit to having no strongly persuasive levers to pull against those who continue to discriminate.

"It is difficult to come to a legal solution," said Horst Haase, a lawyer and member of the parliament, who cosponsored with the mayor the evening pub tour. "A private contract between owners and guests is involved. We don't have the possibility to force the issue. It's more a question of morality than of law."

West Germany has no law like the U.S. Civil Rights Act of 1964 explicitly making it a federal crime to discriminate in public places on the basis of race, creed or religion.

According to West Germany's Basic Law, or constitution, "No one may be prejudiced or favored because of his sex, his parentage, his race, his language, his homeland and origin, his faith, or his religious or political opinions." This has been interpreted by the courts as a clear prohibition against discrimination by any official agency. But the degree to which it applies to private transactions -- say, between a customer and a bar owner -- is still disputed.

Capt. Paul Soter, a white attorney with the U.S. Army Claims Service in Mannheim, is seeking what could become a landmark decision in this area. He and a black student from Burundi were refused entrance into a club in Wuerzburg, so Soter sued the club.

A local court fined the club owner, but an appeals court reversed the ruling. The case is now before the Bavarian supreme court. Significantly, Soter's case is based not on West Germany's Basic Law but on a section in the criminal code stipulating a fine or prison term for someone delivering an insult. The term "insult," however, is not defined in the code.

West German and U.S. military officials meet periodically to review discrimination complaints. In the city of Karlsruhe, for example, the two sides seem to have reached a workable balance.

To repair the image of the loud, boisterous GI there, the Army issued to soldiers a 10-point code of conduct outlining West German laws and customs relating to behavior in German clubs. In turn, Karlsruhe officials have reportedly gained agreement from bar owners to serve all customers, leaving those who get out of hand to be dealt with by local and U.S. military police.