US Vice President Mike Pence arrives in Estonia to reassure Baltic NATO members that are worried about Russia's military activity in the region.
Pence, who will hold talks with Estonian officials on Sunday and Monday, will also visit Georgia and Montenegro later on during his trip.
On Sunday, he will talk with Estonian Prime Minister Juri Ratas about the possibility of installing a US anti-aircraft system there.
Moscow and Tallinn have not had a very amicable relationship since 1991 when Estonia broke free from the Soviet Union and then joined both the European Union and NATO in 2004.
In recent months, Estonia and fellow Baltic states Latvia and Lithuania have been reportedly frightened by Russia's frequent military drills near the region as well as the rejoining of Crimea to Russia after it broke free from Ukraine.
Pence will also meet Estonian President Kersti Kaljulaid and Lithuanian and Latvian leaders, Dalia Grybauskaite and Rajmonds Vejonis, in Tallinn on Monday
The American official is also slated to visit troops from the Enhanced Forward Presence program, under which NATO has sent four battalions to the Baltic states and Poland to strengthen the Western defense alliance's eastern flank.
Pence will reassure Estonians that "the US is a good loyal ally and that they appreciate Baltic sacrifices including their 2 percent of GDP spending on defense and their participation in military operations in Afghanistan," according to Tallinn University international relations specialist Matthew Crandall.
Also, analyst Andres Kasekamp said that "the timing, before Russia's Zapad exercises (in September in Belarus, near the Lithuanian border) shows that the US wants to say: 'We are watching what's happening here very closely and you can be certain of our support.'"
The Zapad exercises have raised concern in Lithuania because they will be conducted somewhat close to the Suwalki gap, a land corridor crossing southeastern Poland.
The corridor is regarded the potential Achilles heel of NATO's eastern flank since a hypothetical Russian offensive there could easily isolate and push the three Baltic countries to the north.