MARIUPOL - The city of Mariupol in southeast Ukraine remains contested, according to a senior US defense official, as Ukrainian forces hold out against “almost a dozen” battalion tactical groups, or BTGs.

“Our assessment is Mariupol is still contested,” the official said Monday. Mariupol, a city which Russia has reduced to rubble in many places, has become the focus of the renewed Russian offensive focusing on the south and east of Ukraine. The city sits on the coast of the Sea of Azov, a strategically important location that would allow Russia to create a continuous land bridge from Donbas to Crimea if the city fell.

The Russians have committed about a dozen battalion tactical groups (BTGs) to the fight in Mariupol, the official said. Each BTG can have as many as 1,000 troops.

“Should Mariupol fall to the Russians, that would free up another almost a dozen battalion tactical groups to be used elsewhere in the east and in the south,” the official said. “But that’s a big ‘if,’ because Ukrainians are still fighting very hard for Mariupol.”

Russian forces have repeatedly struck Mariupol from the air, using both bombs and missile strikes, as well as artillery strikes from the ground, the official continued. The official also says an amphibious assault on Mariupol is a possibility, though the US is not able to independently confirm that such an assault is coming, as the Ukrainians have warned.

Mariupol remains contested as Ukrainian forces resist against about a dozen BTGs

The Russians “do have some amphibious capability certainly in the Black Sea and in the Sea of Azov,” so it’s certainly within the realm of possibility there, the official added.

Russia has added forces to eastern and southern Ukraine The US assesses that Russia has added 11 battalion tactical groups (BTGs) to their forces in the east and south of Ukraine since late last week, according to a senior US defense official, bringing Russia’s total number of BTG’s to 76. “They have added to their capability inside Ukraine,” the official said on a press call, adding that all Russian ground forces are currently focused in the east and south of Ukraine, but the US is unable to pinpoint exactly how the new BTG’s are spread out. Meanwhile, the US has sent four flights of security assistance for Ukraine into the region from the newest round of assistance authorized by US President Joe Biden worth $800 million, the official noted. Another should be arriving “over the next 24 hours,” according to the official, but no details were provided around what equipment was on the flights.