The news from Latvia follows reports that stickers bearing the Wagner Group logo and seeking recruits had been distributed in Warsaw and Krakow.
A new base housing Wagner Group exiles in Belarus is less than 500 miles from the Russian capital.
One diplomat told Newsweek they are "watching and assessing" Wagner arrivals in Belarus, ready to retaliate with sanctions if their presence is confirmed.
NATO countries bordering Belarus have spoken of strengthening their security forces due to the relocation of Wagner Group troops.
The Kremlin is viewing the NATO country's decision to ban as a show of support for news sources inside Russia.
Damaged critical infrastructure could lead to a humanitarian crisis in Ukraine as a frigid winter looms.
A European defense official told Newsweek that top Russian airborne, military intelligence, and army units have taken "severe" casualties since February.
Latvia's foreign affairs minister said Ukraine should be allowed to attack military sites in Russia to fend off strikes on its critical infrastructure.
The president of the Baltic Security Foundation told Newsweek the systems are a "game changer" for the nations.
The reported deaths come after Russia struck Ukraine with dozens of missiles, knocking out energy infrastructure.
The Latvian government said the state of emergency has been imposed "due to the mobilization announced in Russia."
In Kyiv, Egils Levits urged allies not to engage in the "politics of capitulation" and betray Ukraine's wishes.
A report has said all four people believed to be on board the aircraft were German.
Vladimir Solovyov told the Russia-1 program "Full Contact" that if the alliance got involved, "we will have no pity for them."
Latvian Deputy Prime Minister Janis Bordans said that Latvia could restrict the Russian language in workplaces.
Russia's invasion of Ukraine has spurred nearby countries to reconsider their military capabilities, with many now seeking long-range missiles.
Mircea Geoană did not provide any details of a planned deployment, but said there would be "a robust, flexible and sustainable presence" in eastern Europe.
Artis Pabriks told Newsweek that Russia's invasion of Ukraine can only be allowed to end with Kyiv's clear victory.
Putin and other Russian officials have repeatedly warned Russia could use nuclear weapons against NATO nations if they intervene in the Ukraine invasion.
Tomas Jaunzems and his crew arrived at the apartment complex knowing a rescue attempt was imminent.
Countries behave "too boldly" and they don't realize we can "handle them way faster" than Ukraine, a Russian TV panelist warned.
Ahead of Russia's invasion of Ukraine, President Vladimir Putin repeatedly warned the West about NATO's expansion, viewing it as a threat to Russia's security.
A Lithuanian lawmaker fired back at the outspoken editor of Communist Party-owned newspaper The Global Times on Tuesday.
The campaign, known as Ghostwriter, attempts to instill conflict in the intergovernmental military group, obtain confidential information and spy on dissidents.
EU leaders are accusing Belarus and Moscow of weaponizing migrant flows as a diplomatic standoff spirals into a humanitarian crisis.
Top officials from the Baltic states told Newsweek that Moscow and Minsk are weaponizing vulnerable migrants.
Top diplomats told Newsweek President Joe Biden must contain the short- to medium-term Russian threat and face China's existential challenge.
Top diplomats from NATO's Baltic states said the former president's public belligerence belied the alliance's response to Russian aggression.
Top ministers in Latvia, Estonia and Lithuania all told Newsweek they had little hope that Russia would act in good faith over the new natural gas pipeline.