ANKARA, June 16 (Reuters) - Turkey's foreign minister said on Tuesday he told his Russian counterpart about the need to avoid steps in the Black Sea that threatened regional security and Turkey's interests, adding he also repeated Turkey's offer to mediate between Kyiv and Moscow. In recent months, Ukraine and Russia have accused each other of drone attacks on tankers near Turkey's northern coast, including one on a Turkish-owned vessel. Ankara has protested to both Kyiv and Moscow over the attacks.