Russia revealed on Monday that its armed forces had moved nuclear-capable Iskander missiles closer to Europe's borders in response to the US-led deployment of a disputed air defence shield.The advanced version of the Russian missile has a range of 500 kilometres (310 miles) and could potentially be used to take out ground-based radar and interceptors of the new NATO shield.
The announcement prompted fears in the US and neighbouring states such as Poland.
"We've urged Russia to take no steps to destabilize the region," State Department deputy spokeswoman Marie Harf said in response, adding the US had also passed on to Moscow its neighbours' concerns.
Those concerns were voiced earlier on Monday.
Poland's foreign ministry called the planned missile movement "disturbing".
"This is a matter for NATO and we can expect possible consultations and action (...) at the NATO and EU level," added the ministry in a statement.
Estonia, Lithuania and Latvia called the news "alarming".
Latvia's Defence Minister Artis Pabriks, quoted by the Baltic News Service (BNS), said: "It is clear that it is alarming news as it is one of the arguments changing balance of powers in our region."
He added "several Baltic cities" were threatened by the move.