"Your country and your leadership are models of courage, resilience, and democratic values," Harris said in her remarks before the bilateral meeting.
"Together, the United States and Lithuania are making clear that we will stand in defense of an international rules-based order in Europe, in the Indo-Pacific, and around the world," she said.
According to the vice president, "part of the strength of the relationship between the United States and Lithuania is that we stand for common principles and values, and we stand together in defense of the people of Ukraine and the importance of sovereignty and territorial integrity".
"Madam Prime Minister, given Russia's unprovoked and unjustified war in Ukraine, our work together (...) is more important than ever," she said.
Harris reaffirmed Washington's commitment to defending NATO's eastern members, saying that the Alliance is stronger and more united than it has been in decades, despite Russia's attempts to divide the bloc.
"This unity, I believe, is our greatest source of strength," she said.
The US embassy in Vilnius said on Wednesday that Washington would further enhance its military presence in the Baltic countries.
"In Lithuania, this initially includes transitioning the episodic deployments of an armored battalion-sized element and field artillery battery to a persistent rotational presence," it said in a press release.
For the past few years, the US battalion has been deployed at the Pabrade training area close to Vilnius with longer or shorter breaks between rotations.
Simonyte thanked the US for the presence of its troops in Lithuania.
"We're proud to be a host nation to your people, your military man serving for the common benefit of peace and freedom," she said before the meeting.
A company-size unit of around 150 US troops was stationed in Lithuania on a rotational basis in the wake of Russia's annexation of Crimea from Ukraine in 2014.
After three years of company rotations, the US has been deploying battalions more regularly to Lithuania since 2019.