A group American politicians and public figures appealed to U.S. President Donald Trump with the request to tighten sanctions against Russia as much as possible and to provide military assistance to Ukraine in strengthening its defense potential in the Black and Azov Seas.

Some 45 public and political figures sent D. Trump a letter dated December 12, 2018, in which they note that Russia's aggression against Ukrainian ships in international waters near the Kerch Strait and the Sea of ​​Azov represents a serious threat to international security and the free movement of world trade. The letter notes that "Russia's actions require a strong and clear response from the United States."

"Mr. President, you currently have it in your power to swiftly raise the costs on Russia for its latest illegal actions—and by making visible preparations to impose even higher costs for future aggression. The United States must not waver: the costs must rise until Russia’s leaders no longer wish to bear the burden of challenging peace in Europe," the letter says.

The signatories suggest that the American leadership begin with the rigid implementation and observance of the already existing American sanctions against Russia to the maximum extent permitted by law.

"Second, providing additional security assistance to strengthen Ukraine’s maritime capabilities, specifically by providing systems such as radars, coastal defense missiles, ISR equipment, and patrol boats for defense and deterrence against future attack on Ukraine’s Black and Azov Sea littoral zones," the letter says.

"Third, employing the bully pulpit of your office to ensure that all European allies hold firm in maintaining their own financial penalties on Russia for its previous illegal actions in Crimea and press our allies to maintain a robust NATO maritime presence in the Black Sea in order to defend freedom of navigation.

Fourth, immediately imposing either new or more restrictive sanctions on Russian financial instruments and banks, including Vnesheconombank (VEB), Promsvyazbank, Gazprombank, and the Russian Direct Investment Fund (RDIF)," the letter says.

The fifth step, proposed to D. Trump by the signatories, is to rally the European allies of the United States around the goal of convincing the German government to suspend official support for the Nord Stream-2 gas pipeline due to the latest Moscow aggression.

The letter was signed by 45 people, including American-British journalist and writer Anne Applebaum and several retired ambassadors and U.S. generals.