Russia did not immediately or directly respond to the allegation, but Russian news agencies cited the Federal Security Service (FSB) as saying it had incontrovertible proof that Ukraine had orchestrated what it called a "provocation" and would publicise its evidence soon.[57] A report by the Russian FSB said that Ukraine had not followed the official procedure required for passage through the strait, namely that the port authority in Kerch should be informed 48 and 24 hours in advance of any movement, with an official confirmation 4 hours before the passage.[2] It also said the Ukrainian ships had been manoeuvring dangerously and intentionally ignored FSB instructions in order to stir up tensions.