Tunisia's defence ministry said the United States was a main partner in the effort to build the Tunisian army's operational capability.
The United States is looking to use one of its Security Force Assistance Brigades in Tunisia, its military said on Friday, amid concern over Russian activity in Libya.
Libya's civil war has drawn in regional and global powers, prompting what the United Nations has called a huge influx of weapons and fighters into the North African nation, in violation of an arms embargo.
"As Russia continues to fan the flames of the Libyan conflict, regional security in North Africa is a heightened concern," the United States Africa Command said in a statement.
"We’re looking at new ways to address mutual security concerns with Tunisia, including the use of our Security Force Assistance Brigade," it added.
Russian military personnel have delivered 14 MiG 29 and Su-24 fighter jets to the Libyan National Army's (LNA) Jufra air base, the US military said on Wednesday, despite denials by the LNA and a Russian member of parliament.
Egypt, Russia and the United Arab Emirates support the eastern-based Khalifa Haftar's LNA, which launched an offensive last year to seize the capital Tripoli.
In a statement, Tunisia's defence ministry said the United States was a main partner in the effort to build the Tunisian army's operational capability.