Russia's parliament has threatened economic sanctions in response to a language reform in neighbouring Latvia that will see older schoolchildren taught in Latvian rather than Russian.

The call for sanctions further raises tensions with Latvia, Lithuania and Estonia, members of the European Union and Nato who have been wary of Vladimir Putin's promises to “defend the rights” of Russian speakers in other countries.

On Tuesday, the leaders of the three countries expressed their concern about Russia's more aggressive foreign policy at a meeting with US president Donald Trump in the White House.

Although Latvian is the official language in that former Soviet republic, a quarter of the population are ethnic Russians, and nearly 100 state-funded schools offer Russian or bilingual teaching.