German authorities detained a Ukrainian national The arrest occurred in Italy's Rimini province The suspect is believed to have orchestrated the 2022 Nord Stream pipeline explosions The explosions damaged pipelines transporting Russian gas to Germany The explosions occurred on September 26, 2022 The arrest followed underwater explosions Nord Stream 1 and Nord Stream 2 pipelines were targeted Nord Stream 1 supplied gas to Germany Nord Stream 2 was never operational Germany suspended Nord Stream 2 certification before the invasion Serhii K. was arrested on a conspiracy charge German prosecutors withheld the suspect's full identity The suspect will be transferred to Germany for trial No group has claimed responsibility for the explosions Ukraine denies involvement German officials urge caution amid accusations involving Russia and the U.S.