USS Mount Whitney, the U.S. 6th Fleet flagship, is anchored in Istanbul on Aug. 18, 2023, during a scheduled visit to Turkey. (Mario Coto/U.S. Navy)

The amphibious command ship USS Mount Whitney, which once drew the ire of Russian President Vladimir Putin, departed Istanbul on Monday after a weekend visit focused on strengthening ties with key NATO ally Turkey, according to the Navy.

The vessel, which is the U.S. 6th Fleet flagship, arrived for a scheduled port call Friday, the Navy said in a statement the same day. The visit appeared to make the Mount Whitney only the second American warship to venture so near the Black Sea since the start of the Russia-Ukraine war in February 2022.

In February, the destroyer USS Nitze was the first American warship to travel in proximity to the Black Sea, making a brief stop in Istanbul on its way to Golcuk Naval Base, on the east side of the Sea of Marmara.

Istanbul is situated along both sides of the Bosporus near its entrance from the Sea of Marmara. The strait stretches about 19 miles before it reaches the Black Sea.

Other U.S. warships, notably destroyers USS Bainbridge and USS Mitscher, also have visited Turkey since the war started, but none traveled as close to the Black Sea as Mount Whitney and Nitze.

Petty Officer 1st Class Donald Cooney and Petty Officer 3rd Class Alexander Ramirez prepare to raise the ensign aboard the USS Mount Whitney in Istanbul on Aug. 18, 2023. Mount Whitney, the 6th Fleet flagship, homeported in Gaeta, Italy, left Istanbul on Monday. (Mario Coto/U.S. Navy)

The destroyer USS Arleigh Burke was the last American warship to transit the Black Sea, leaving in December 2021, according to the ship-watching website turkishnavy.net.

Weeks earlier, Putin railed against the U.S. Navy’s presence in the Black Sea, saying the Russian military had Mount Whitney in the crosshairs as it transited the sea on routine NATO operations.

The port call in Istanbul came just days after the first civilian cargo ship carrying grain left the Ukrainian Black Sea city of Odesa on Wednesday in a test of Russia’s threat to treat commercial vessels transiting the Black Sea as military targets.

Last month, Moscow backed out of a deal brokered by Turkey and the United Nations that had allowed Ukraine to export its grain.

The Hong Kong-flagged Joseph Schulte safely traveled through a temporary humanitarian corridor established in the Black Sea, exiting through the Bosporus on Friday, Politico reported the same day.

Earlier in the week, Russia said it had fired warning shots at a cargo ship traveling in the southwestern Black Sea on Aug. 13. The Kremlin released video of Russian troops boarding the vessel and interrogating its crew.

In an Aug. 16 post to his official account on X, formerly known as Twitter, retired Navy Adm. James Stavridis, a former NATO supreme allied commander in Europe, called the Russian actions “piracy,” later telling Politico the behavior could “force the alliance to intervene.”

The U.S. is in talks with Turkey, Ukraine and other countries in the region about increasing the use of alternative routes, such as the Danube River, to export Ukrainian grain, The Wall Street Journal reported Aug. 15.

Turkey closed the Bosporus to most warships shortly after Russia’s full-scale invasion of Ukraine.

Only military vessels whose homeport is in the Black Sea — those from Bulgaria, Georgia, Romania, Russia, Turkey and Ukraine — may use the strait to enter or leave the sea, according to Turkish policy invoked at the time. Merchant ships are not restricted.