Amid spreading incidents of anti-British violence, Britain cautioned its citizens traveling abroad yesterday to "keep a low profile" in the aftermath of a riot between English and Italian soccer fans last week that killed 38 persons.

In Brussels, Belgian Prime Minister Wilfried Martens attended a memorial service for 25 of the victims, 22 of them Italians, and said sports and public officials should find a way "to put an end to this mad race toward violence in sports and in our cities."

Martens said Belgium will ask Britain and Italy to prosecute those who took part in the rioting. In Rome, prosecutor Alfredo Rossini forbade burial of the 31 Italian victims until autopsies could be conducted to determine the "precise cause" of death.

The British government's warning to Britons traveling abroad was issued, according to a Foreign Office spokesman, because "there could well be some anti-British feeling, in particular in Italy, and we're advising anyone traveling to the continent to keep a low profile," Reuter reported.

There were reports from several Italian cities and from Paris of violence and harassment directed against Britons and their vehicles.

London newspapers carried accounts yesterday of an English bus being badly damaged by angry Italians in Diano Marina, Italy, and reports from the British Embassy in Paris that at least 50 cars with British license plates were attacked Friday, The Associated Press reported.

In Milan, a British visitor was beaten by a group of youths outside his hotel and was treated at a hospital, Reuter reported. In Rimini, youths stoned two empty British buses and shouted insults at British tourists. In Sassari, Sardinia, anti-British slogans were painted on walls near hotels and restaurants.

A spokesman for the British Embassy in Rome told Reuter the mission had received "a high volume of phone calls, some of them abusive," about the riot, which apparently began when supporters of a Liverpool team attacked supporters of an Italian team.

British Foreign Secretary Geoffrey Howe, visiting Brussels, expressed concern over anti-British feeling in Europe. He said he believed Britain's general reputation would be "sufficiently widely respected for that phase not to last long" and said he would fully support tough penalties for those fans found guilty in Belgian courts of criminal offenses.

Police in Brussels disarmed a bomb early yesterday at the central Brussels branch of the British shopping chain Marks and Spencer. Police said no one had claimed responsibility for the bomb and it was not known whether it was connected to the soccer riot.

In Sydney, Australia, players for two other English and Italian teams paused before a match to honor the victims of the riot, United Press International reported. It was the first game between teams of the two countries since the tragedy and it was played without incident.

At Liverpool, 2,000 persons gathered Friday night in the city's metropolitan cathedral for a requiem mass for those who died in Brussels. The Union Jack and the Italian and Belgian flags stood crossed at the altar as the congregation sang hymns. Many people, including members of the Liverpool soccer team, wept.

In Mexico City, members of the Italian and English national soccer teams preparing for a tournament there sat together at a mass held in memory of the victims of the riot in Brussels. The two teams are scheduled to play on Thursday.