MOSCOW — Thousands of riot police deployed around central Moscow Wednesday to prevent possible ethnic clashes after the weekend rioting by racist hooligans fueled rumors that minorities could try to retaliate.Scuffles erupted outside Kievsky train station, which is popular with traders from the Caucasus, as hundreds of baton-wielding riot police in dark helmets rounded up some young men and teenagers shouting racist slogans. Police also detained dozens of potential troublemakers from the Caucasus and confiscated knives and other weapons from them, officials said.Resentment has been rising among Slavic Russians over the growing presence in Moscow and elsewhere of people from the southern region of Caucasus, the home of numerous ethnic groups, most of them Muslim. People from other parts of the former Soviet Union, including Central Asia and Azerbaijan, also face ethnic discrimination and are frequent victims of hate crimes.The area around Kievsky station is feared to be a target of those who rioted outside the Kremlin, mainly soccer fans, who chanted "Russia for Russians!" during Saturday clashes that left dozens injured. Many soccer fans are linked with neo-Nazis and other radical extremist groups.