On Sunday, two Ukrainian ships and a tugboat, which were travelling from Odessa on the Black Sea to Mariupol on the Sea of Azov, were shelled and later seized by Russian special services.
Russia said the three Ukrainian vessels made an unauthorised passage through Russian territorial waters. Russia's Federal Security Service (FSB) confirmed that it fired on the vessels to force them to stop, and then seized them.
Presidential aide Krzysztof Szczerski said at a press conference in Warsaw that President Duda and President Poroshenko on Monday discussed the situation in the Sea of Azov, over the phone. During the half-hour telephone conversation, held on the initiative of the Ukrainian leader, he briefed the Polish president on Sunday's events in Ukraine and possible development scenarios in the coming days.
"Ukraine's president assessed and described the situation as serious and dangerous for the country. In Poroshenko's opinion, Russia's actions are clearly marked by acts of aggression, as defined by international law," he added.
Szczerski reported that according to Poroshenko, the Ukrainian vessels were "attacked" in neutral waters and that there was no military response from Ukraine.
Referring to the current situation in the Sea of Azov, Polish President's aide Krzysztof Szczerski declared on Monday that increasing the sanction regime against Russia should be considered and discussed with allies in the international forum.
Krzysztof Szczerski told reporters that President Poroshenko's motion to impose martial law in Ukraine was another subject of the phone conversation held by the two heads of state.
"(...) The Ukrainian president assured President Duda that this is an extraordinary measure, which is limited in time and which will have no influence on the course and schedule of democratic procedures, including elections, in Ukraine," minister Szczerski underlined. (PAP)