The US Pentagon said that the military buildup was greater than the one during 2014, and it was not clear whether it was for training purposes.
Mr Borrell confirmed that for the time being, no sanctions or expulsions of Russian diplomats had been planned.
Meanwhile, Washington is threatening more sanctions in case Navalny were to die in prison.
In a recent report, head of Oxford-based think-tank Euro Intelligence Wolfgang Munchau explained why Germany is not taking a similar approach.
Mr Munchau argued the influence of Russian President Vladimir Putin in Angela Merkel’s country is visible in many areas.
He wrote: “The Germans, too, follow the plight of Navalny with interest.
“But there is no discussion about sanctions.
“And certainly no discussion that would link the Nord Stream 2 pipeline to Navalny’s health.
“Merkel may have given Navalny her emotional support when she visited him at a Berlin hospital.
“But German politics has been and remains on the side of Putin.”
The Nord Stream 2 project is an underwater twin pipeline that would transport natural gas from Russia directly to Germany.
At a length of 1,230 kilometres, it is to follow the route of the existing Nord Stream twin pipeline underneath the Baltic Sea.
Since it was first planned, Nord Stream 2 has drawn criticism from the US, where both the Democratic and Republican parties believe that the project would increase Europe’s dependence on Russia for natural gas, thus boldening its President Vladimir Putin.
According to Mr Munchau, though, the Nord Stream 2 project is a “monument to the Russo-German relationship” and probably “the most important strategic partnership in Europe right now”.
He added: “We see Russia’s influence in Germany in other areas too.
“This weekend we heard about the rise of vaccine-tourism.
“For €1999 (£1742) a tour operator organises two separate flights to Moscow for two vaccination appointments, plus another €300 (£262) for the vaccine itself.
“This is interesting not only because Sputnik V has not even been approved in the EU, but also because it is a vaccine of the same type as the much-maligned AstraZeneca. ”
Things could become worse if newly elected CDU leader Armin Laschet wins Germany’s Chancellorship in this year’s election.
Described as the “continuity candidate”, Mr Laschet has for the most part supported Mrs Merkel‘s politics.
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Under his leadership relations with Russia might take an unexpected turn as archive reports show Mr Laschet to be in favour of close ties with Mr Putin.
In Germany he is known as a Russlandversteher, a derogatory term for people who take a soft and sympathetic stance on Mr Putin and Russia, according to Politico.
In 2019, looking back at the policy of détente in the Seventies during the Cold War – the period which marked an easing of tensions between Western powers and the Soviet Union – Mr Laschet said: “Back then, in a tense situation with a totalitarian communist system, threads of conversation were established.
“Then it must be possible for us today too.
“We need Russia for many questions in the world.”
He continued: “There are many conflicts where we have to move forward without giving up our position under international law, for example on Crimea.
“You can speak plainly and still cooperate in other fields and keep talking.”