President of Ukraine Petro Poroshenko has said that Russia is preparing to establish air control over the territory where gas and oil pipelines to Europe pass. He said specific steps are needed to stop Russian aggression.

"I am convinced that the time of general political declarations has already passed and the aggression against Europe is unacceptable," he said in an interview with the Italian daily Corriere della Sera, the presidential press service reported on Saturday.

The president stressed that concrete steps should be taken to stop Russian aggression, such as "blocking the Nord Stream 2 project, strengthening NATO's presence in the Black Sea, introducing new sanctions against those responsible for the crisis in the Azov Sea, forbidding Russian ships from entering the European ports, supporting Ukraine in the political, economic and military spheres."

According to the president, attempts by some to charm the Russian President Vladimir Putin will only provoke a new attack by Russia on world order, freedom, and core values of democracy.

The president also stressed that there are two million people in Crimea who are terrorized by repressions, in Donbas there are more than 11,000 dead over the past four years and 1.5 million displaced persons.

He emphasized that Ukrainians never wanted to intensify the crisis.

"The clashes in the Kerch Strait were planned in Moscow. After the invasion of Donbas and aggression in Crimea, now they want to take the Azov Sea, force us out and take more our territories. Those who allow themselves to be misled by Kremlin propaganda are naive," the president stressed.

According to him, at present the tension in the Sea of Azov has attracted the attention of the international community, but at the same time Russian fighter planes violate Ukrainian airspace in different parts of the border and in the Baltic States.

"They are also preparing to take air control of the territory where gas and oil pipelines pass through delivering hydrocarbons to Europe. Putin threatens NATO's eastern borders. If you remain silent, Putin will know that he can continue to expand and gain new benefits," he stressed.

At the same time, he noted the joint European position and the requirement for the Kremlin to observe international law. In particular, the requirement for Russia to free Ukrainian sailors and to guarantee free navigation in the waters of the Kerch Strait.

He thanked U.S. President Donald Trump for his decision not to meet with Putin at the G20 summit.

"Now the Russian leader is in isolation. I am also grateful for the actions of Mrs. Merkel [German Chancellor Angela Merkel] to curb the expansion of Moscow. But this does not mean that Russians will not continue their invasion policy," he added.