KIEV, December 4. /TASS/. Ukrainian President Pyotr Poroshenko has instructed Justice Minister Pavel Petrenko to prepare a lawsuit against Russia over the November 25 incident in the Kerch Strait, the presidential press service said on Tuesday.

"The justice minister has been instructed today to complete preparations to sue Russia over this act of aggression so that those who gave orders can be held accountable," Poroshenko said at a meeting with the families of Ukrainian sailors arrested for violating the Russian border in the Kerch Strait.

The Ukrainian president was also confident that Kiev’s foreign partners would take measures against those involved in the sailors’ detention. "It concerns those who attacked them and those who brought them before a kangaroo court. The entire world should respond to this incident. We are not going to let anyone go unpunished," Poroshenko said. "A group of lawyers, including foreign ones, is currently working on the possibility of holding Russia responsible," he added.

The Ukrainian president told one of the country’s TV channels earlier that Kiev planned to send complaints to the United Nations over the Kerch Strait incident.

Kerch Strait incident

On November 25, three Ukrainian navy ships illegally crossed Russia’s border and tried to carry out some illegal actions in Russian territorial waters later in the day. They ignored legitimate demands to stop issued by vessels belonging to the FSB Border Service and the Black Sea Fleet and continued maneuvering dangerously. In order to stop the Ukrainian ships, weapons had to be used. The three vessels were detained in Russian territorial waters. Three Ukrainian military servicemen suffered light wounds and were provided with medical assistance. A criminal investigation has been opened into the border incident.

Moscow branded Kiev's stunt in the Kerch Strait as a dangerous provocation, while the European Union and NATO called for a de-escalation of tensions, while Kiev declared a 30-day martial law.

The Ukrainian ships’ crew members, 24 Ukrainian nationals, have been arrested until January 25, 2019, and transferred from Crimea’s Simferopol to Moscow.