U.S. President Joe Biden declared last April that "no ship sailing under the Russian flag, or owned or operated by Russian interests, will be allowed to call at U.S. ports or enter U.S. shores."

"We have extended for one year the ban on Russia-linked ships entering U.S. ports," it said.

Biden said the decision was based on the Russian government's "continuing policies and actions in its unjustifiable, unprovoked and brutal war against Ukraine."

Some Russian experts pointed out that given the massive sanctions imposed by the U.S. on Russia, few Russian ships will dock at U.S. ports or enter U.S. shores, so the sanctions are purely symbolic.