Romanian President Nikusor Dan told the BBC that there is no doubt that the drone that hit a multi-story apartment building in Galati is Russian.
According to him, the device was "completely identical" with another drone found in Romania a few weeks ago that failed to explode.
Dan said that Russia had attacked western Ukraine with a swarm of drones, and that one of them had entered Romanian airspace after being intercepted by Ukrainian air defenses.
Russian President Vladimir Putin had previously disputed that version, saying that such conclusions required expert analysis and noting cases of Ukrainian drones flying over other countries.
After the incident, Romania closed the Russian consulate in Constanta and expelled the consul. Dan said that Bucharest was also considering expelling the Russian ambassador. He added that he had received assurances of support from the United States.