VILNIUS - Prime Ministers Ingrida Simonyte of Lithuania, Krisjanis Karins of Latvia and Kaja Kallas of Estonia said in a statement on Thursday that they joining the G7 Declaration of Support for Ukraine.
"We firmly believe that only NATO membership will provide Ukraine with security guarantees and a credible deterrent needed to avert future aggression by expansionist Russia," they said in the joint statement.
The three Baltic leaders expressed their "unwavering support and solidarity with the people and the government of Ukraine who are heroically defending the freedom, independence, sovereignty and territorial integrity of their country".
"We recognize that Ukraine's courageous fight helps protect Euro-Atlantic security and the rules-based international order," they said.
Simonyte, Karins and Kallas said they "have stood together with Ukraine since day one of Russia's unprovoked and brutal aggression" and pledged to keep supporting it "until victory " and to "continue contributing to international efforts to safeguard its independence, sovereignty, security, democracy, and prosperity".
"At the NATO Vilnius Summit, the Allies agreed that Ukraine's future is in NATO," they said. "We will continue our steadfast support for Ukraine on its path to join the Alliance as soon as possible."
"Ukraine's NATO membership will also substantially strengthen Euro-Atlantic security and stability."
The Baltic prime ministers also pledged to "work closely with Ukraine on its way to EU membership" and said they "look forward to the start of accession negotiations in 2023".
Latvia announced last week that it was joining the G7 declaration separately from its neighbors.
Simonyte then said that the Baltic countries had considered doing so together, but that in the course of the talks "the Latvian government decided to rush into it for reasons known to it".
At last month's NATO summit in Vilnius, the G7 countries pledged long-term military support to Ukraine to help it fight the invading Russian forces and stop any recurrence of war.
Ukrainian President Volodymyr Zelensky called the declaration a significant security victory.