The letter, which is dated January 9 says the signatories are "eager" to work with Trump's administration "to sustain our powerful transatlantic Alliance, jointly defending our way of life at a time of great peril."
The full text of the letter can be read via the tweet below from former Estonian President Toomas Hendrik Ilves.
Among the signatories from Latvia are former President Vaira Vike-Freiberga and current Saeima deputy Ojars Eriks Kalnins, who is the chairman of the Saeima's Foreign Affairs Committee.
However, Kalnins told LSM January 10 he had signed in a purely personal capacity.
"I signed it on my own behalf, as I thought it was a good idea. I think the letter conveys good ideas and I think it's important the Trump administration hears these voices," Kalnins said.
As yet, no reaction had been received, he added.
Other people signing the letter, which says it would be a mistake to lift sanctions against Russia as part of a "grand bargain" include former Polish Foreign Minister Radoslaw Sikorski, former Swedish Prime Minister and Foreign Minister Carl Bildt and former Czech Foreign Minister Karel Schwarzenberg.
"A deal with Putin will not bring peace. On the contrary, it makes war more likely. Putin views concessions as a sign of weakness. He will be inclined to test American credibility in frontline NATO allies, such as Estonia, Latvia, Lithuania and Poland," the text warns.
"He may use not only military intimidation, but also cyber-attacks, energy and economic pressure, espionage, psychological warfare, disinformation and the targeted use of bribery. As Russia’s neighbors, we are familiar with these techniques. Countering them requires greater strength, solidarity and resolve from the West—not more accommodation."
You can also read the full text HERE.