Russia signalled concern at Estonia's treatment of its large ethnic Russian minority yesterday, comparing language policy in the Baltic state with what it said was a call in Ukraine to prevent the use of Russian.
This came as US President Barack Obama imposed more sanctions on Vladimir Putin's inner circle and a "crony bank" for Russia's elite, while threatening to target Russia's broader economy over the Ukraine crisis.
The new US measures targeted a new list of 20 lawmakers and senior government officials and other key figures in addition to 11 people already sanctioned by Washington.
As Washington unveiled its latest sanctions, Moscow hit back with its own tit-for-tat measures targeting members of Obama's inner circle, including deputy national security adviser Ben Rhodes, key political aide Dan Pfeiffer and Caroline Atkinson, a top international economic official in the administration. The blacklist also includes the speaker of the House of Representatives John Boehner, senators Mary Landrieu, John McCain and Daniel Coats.
Russia has defended its annexation of Ukraine's Crimea peninsula by arguing it has the right to protect Russian-speakers outside its borders.
Russia fully supported the protection of the rights of linguistic minorities, a Moscow diplomat told the United Nations Human Rights Council in Geneva.
"Language should not be used to segregate and isolate groups," the diplomat was reported as saying. Russia was "concerned by steps taken in this regard in Estonia as well as in Ukraine", the Moscow envoy was said to have added.
The reference to linguistic tensions in another former Soviet republic comes at a highly sensitive moment.
The text of the Russian remarks, echoing long-standing complaints over Estonia's insistence that the large Russian minority in the east of the country should be able to speak Estonian, was not immediately available.
Amid the growing Crimea crisis, Estonia, Latvia and Lithuania - which like Ukraine were all parts of the old Soviet Union - have expressed growing apprehension over Moscow's intentions.
US Vice-President Joe Biden is currently in the Lithuanian capital Vilnius as part of a trip to reassure the three countries and all EU and Nato members of Washington's support.