New Delhi, Feb 26 (IANS): In the latest alarming development, a senior US defence source has said that they believe Russia has launched an amphibious landing with thousands of naval infantry to the west of the key southern coastal city of Mariupol, The Guardian reported.

While the claim had few details, a video posted on social media earlier appeared to show a column of Russian armoured vehicles, including T-72B3 tanks and BMP-3 armoured vehicles, moving through the coastal town of Prymorsk, which is located between Melitopol and Mauripol, the report said.

Describing the "amphibious assault" underway from the Sea of Azov, a senior US defence official told reporters on Friday that Russians "putting potentially thousands of naval infantry ashore there".

"The general assumption is they are going to move towards the northeast, towards Mariupol and the Donbas region," the official said.

Several social media accounts in the region also show images and accounts of volleys of Russian Grad missiles hitting targets near Mariupol late on Friday afternoon, The Guardian reported.

If the account of the landing is confirmed as true, the aim would appear to be to allow Russian marines to link up with forces further east in the Donbas region, the report said.