The arrest was confirmed by Elena Martinonienė, spokeswoman for the Prosecutor General's Office.
The investigation is controlled by Tauragė prosecutors, with the decision on the supervision measure made by a Tauragė court.
The Russian citizen was apprehended by officers of the Pagėgiai unit Ročiškės checkpoint in the Lithuanian territory in early hours of Saturday after he had swum across the River Šešupė that runs along the border between Lithuania and the Russian Kaliningrad region. The man did not have any ID on him, telling the Lithuanian border guards he was a border officer of Russia. 15min.lt news portal said the man had been detained at around 7 a.m. local time on Saturday.
Interior Minister Eimutis Misiūnas has confirmed to BNS that the Russian citizen had been under strong influence of alcohol at the time of the arrest.