The Utah senator has been critical of Trump throughout his presidency.
"As with all activity in the region, we are aware of and closely monitoring the exercise," U.S. European Command spokesperson Navy Lieutenant Commander Russ Wolfkiel told Newsweek.
"China and Russia are united like a mountain, and their friendship is unbreakable," Chinese Foreign Minister Wang Yi said.
The Polish National Defense Ministry told Newsweek it "assesses that recent anti-Polish narrative expressed by authorities of some nations participating in the exercise is motivated mainly by their internal propaganda needs."
"This is just the beginning," Belarusian President Alexander Lukashenko warned as he cracked down on protests to retain power and shored up ties with his Russian ally.
The European Union and the U.S. have not accepted Belarus' August election results, as large anti-Lukashenko demonstrations have persisted within the country.
Mystery had surrounded the fate of Maria Kolesnikova, who witnesses had seen being bundled into a car by masked men in Minsk.
Protests have been ongoing since the disputed election in which Alexander Lukashenko claimed victory.
"This exercise is a demonstration of partnership between NATO Allies aimed at improving interoperability, and is not directed toward a particular country or adversary," the 41st Field Artillery Brigade's Major Joseph Bush said.
Russia and Belarus both held drills around Baltic NATO states Lithuania and Poland, accused by Moscow and Minsk of instigating unrest against longtime President Lukashenko as U.S. and Russian jets met across the world.
"Russia wasn't and isn't interfering with Belarusian affairs," the Kremlin said as Moscow officials accused neighboring NATO nations of "external interference in the affairs of a sovereign state."
"Latvia considers that the only solution is new presidential elections," the Baltic country's foreign service told Newsweek of neighboring Belarus, where President Alexander Lukashenko warns against an outside plot against him.
The foreign ministries of Poland and Lithuania tell Newsweek they are closely monitoring Belarusian border exercises, as President Alexander Lukashenko accuses them of hatching a U.S.-led plot against him.
"I mean the stars are aligned. The best timing to inject 'order' is when a society is in chaos, especially given the power vacuum," a senior U.S. intelligence official told Newsweek.
"Two airplanes full of employees were flown in from Russia. They are taking over our responsibilities," Belarus 3 director Alena Martinovskaya said.
The Russian president is weighing up his options as protests and a brutal crackdown continue in neighboring Belarus after the disputed presidential election.
"Russia pointed out that foreign attempts to interfere in the country's domestic affairs were unacceptable," the Kremlin said in a statement.
Tens of thousands of people took to the streets in Minsk on Sunday to demand Lukashenko's resignation.
Secretary of state told Radio Free Europe he had no worries about the U.S.'s ability to take a tough line with authoritarian regimes.
President Alexander Lukashenko—who has held power for almost three decades—is accused of rigging Sunday's vote to secure a sixth term in office.
The video emerged as protesters and riot police clashed in Belarus' capital Minsk and other cities in the wake of Alexander Lukashenko's presidential election victory.
Belarus's president Alexander Lukashenko has risked his relationship with Putin over the arrest of Russian men he accuses of being sent to destabilize Sunday's election.
Opposition supporters were inspired by the Soviet-era band Kino's song "Changes," which was played at the event in the center of Minsk ahead of Sunday's election.
Belarusian media reports that Maria Moroz, who heads the election campaign of Tikhanovskaya, has been detained.
Svetlana Tikhanovskaya is posing a genuine challenge to Alexander Lukashenko's rule, ahead of an apparent push from Russia to incorporate Belarus.
President Alexander Lukashenko claims the arrested men were going to destabilize next week's ballot, in which he faces a popular opposition candidate.
Belarus says it arrested 33 Russian mercenaries who were sent to "destabilize" the country ahead of elections in which President Alexander Lukashenko is being challenged.
Belarusian President Alexander Lukashenko has been in power since 1994, but has accused Russia of trying to undermine him ahead of elections in August.
Belarus will continue to hold its annual military parade this week, despite experiencing one of the worst coronavirus outbreaks in Europe.