As the flotilla, which consisted of two gunboats and a tugboat, approached the Kerch Strait, the Russian coast guard said they repeatedly asked the Ukrainian vessels to leave what they referred to as "Russian territorial waters". They said that the vessels had not followed the formal procedure for passage through the strait, that the Ukrainian ships had been manoeuvring dangerously, and that they were not responding to radio communications.[9][17][18] Ukraine said that it had given advance notice to the Russians that the vessels would be moving through the strait, that the ships had made radio contact with the Russians, but received no response, and cited the 2003 treaty against the assertion that the ships had entered Russian territorial waters.[4][5][21] The Russians tried to halt the Ukrainian ships, but they continued moving in the direction of the bridge.