The Kremlin said on Tuesday it would not heed calls by some Western countries for sanctions over Russia's detention of poisoned opposition politician Alexei Navalny because his case was a purely domestic matter.

Navalny was detained on Sunday after flying back to Russia for the first time since he was attacked with a military-grade nerve agent last summer while traveling in Russia's east, and has urged Russians to take to the streets in protest.

Lithuania, Latvia and Estonia want the European Union to respond with sanctions against Moscow.

"We hear these statements, but we cannot and don't plan to take these into account," Kremlin spokesman Dmitry Peskov told reporters on a conference call.

"This is about a Russian citizen not complying with Russian law. This is an absolutely domestic matter and we will not allow anyone to interfere in it."

Peskov said Navalny had genuine questions to answer about violating his parole conditions for a suspended prison sentence.

Navalny has been placed in pre-trial detention for 30 days. In 2014, he received a three-and-a-half year suspended sentence for embezzlement, in a case that he says was fabricated for political reasons.

Peskov also dismissed as nonsense the notion that President Vladimir Putin fears Navalny.

"Different statements about someone being afraid of someone else are absolutely nonsense," he said.

Peskov said Navalny's calls for Russians to take to the streets over his detention were alarming, but that the Kremlin did not fear mass protests.