WASHINGTON -- The United States has condemned what it calls Russia’s "harassment" of international shipping in the Sea of Azov and the Kerch Strait, saying it is a further example of Moscow’s attempts to “destabilize” Ukraine.

The State Department on August 30 accused Russia of impeding hundreds of commercial vessels since April by limiting the size of ships that can transit the strait, the only path to reach Ukraine’s territorial waters in the Sea of Azov from the Black Sea.

"Russia's actions to impede maritime transit are further examples of its ongoing campaign to undermine and destabilize Ukraine, as well as its disregard for international norms," the State Department said.

"We call on Russia to cease its harassment of international shipping in the Sea of Azov and the Kerch Strait," it said.

It added that the United States continues to support Ukraine's sovereignty and territorial integrity, including its territorial waters.

There was no immediate response from Russian officials.

Russia in 2014 seized and annexed Ukraine's Crimea region, leading to a series of sanctions being imposed against Moscow by the West, which has not recognized the annexation.

In 2016, Russia launched its $3.7 billion Crimean Bridge project to link the occupied Ukrainian peninsula with southern Russia across the Kerch Strait.

The move led to condemnation and additional sanctions from Kyiv and Western governments.

In mid-May, following the bridge's completion, Russia reportedly moved naval vessels, including warships from its Caspian Flotilla to the Sea of Azov, citing a need for stepped-up security around the new structure.

Since then, Russia has detained more than 148 Ukrainian and foreign merchant ships -- many more than once -- and interrogated their crew members, Ukrainian officials, port authorities, local shipping companies, and experts told RFE/RL.

Ukraine on August 29 said it would soon boost its naval presence in the Sea of Azov.

Navy Commander Ihor Voronchenko said the move would be made "to ensure solid protection of the entire perimeter and peaceful industrial activity" in the sea.