It was only in 1997 that the ships and equipment of the Black Sea Fleet were officially divided between the two countries. The new Russian formation retained its historic name "Black Sea Fleet". Under the terms of a negotiated lease agreement it was also granted rights to use the majority of its bases on the Crimea Peninsula, Ukraine on a renewable ten-year lease basis at least until 2017. The newly established Ukrainian Naval Forces received dozens of vessels (mostly obsolete or inoperative, not unlike some of those retained by Russia) and some shore-based infrastructure. However, the Russian Navy lost several important facilities, most notably the "NITKA" (Russian acronym for "Scientific testing simulator for shipborne aviation") naval aviation training facility in Saky, and the special forces base in Ochakiv. The process of fleet division remained painful since many aspects of the two navies' co-existence were under-regulated, causing recurring conflicts.