(CNN) - The awkward camera angle is meant to hide the fact that the owner of the phone is filming, but there is no mistaking the outlines of the heavy cargo being deposited on the dock in the Yemeni port of Aden last week.

The distinctive shape of the US-made Oshkosh armored vehicle stands out in the early morning darkness, a piece of military hardware that is currently at the heart of a standoff between some American lawmakers and President Donald Trump's administration.

Aden is controlled by the Saudi-led coalition in Yemen, whose main partners are continuing to ship American-made weapons into the country despite bipartisan outrage in Congress over the way the US is backing Riyadh in this bloody and bitter conflict.

This footage showing the unloading of a variety of US-made arms -- which was filmed illicitly at the offloading site, then obtained and verified by CNN -- is itself contentious. Multiple witnesses told CNN that Yemeni authorities, backed by the Saudi-led coalition, have been arresting and questioning those they suspect of leaking it to the media.