The Defense Department announced Monday a $125 million aid package for Kyiv as part of its ongoing Ukraine Security Assistance Initiative.
A Pentagon statement said the package includes two armed Mark VI patrol boats to help Ukraine "patrol and defend its territorial waters."
It also includes additional training, counter-artillery radars, medical support, and satellite imagery and analysis, and improvements that will allow Ukraine to improve interoperability with NATO.
"This action reaffirms the U.S. commitment to providing defensive lethal weapons to enable Ukraine to more effectively defend itself," Pentagon press secretary John Kirby told reporters Monday.
The two patrol boats will give Kyiv a total of eight such vessels to operate in Ukrainian waters.
According to the boat's manufacturer, the vessels are designed to patrol in shallow waters, as well as around harbors and bays.
Last June, the State Department approved the sale of up to 16 of the patrol boats to Ukraine, along with gun systems and infrared radar, for an estimated cost of $600 million.
The aid announced Monday is just the first part of a larger $275 million package approved by Congress for fiscal year 2021.
The Defense Department said the final $150 million would be released once the State Department "certifies that Ukraine has made sufficient progress on key defense reforms."
"We obviously continue to encourage Ukraine to continue to enact reforms, to modernize the defense sector in line with NATO principles and standards," Kirby said.
Those reforms include an increased focus on civilian control of the military and continued modernization of Ukraine's defense sector.
During an address at the virtual Munich Security Conference last month, U.S. President Joe Biden called standing up for Ukraine's territorial integrity a "vital concern."