Ukraine crisis: US sanctions target Russia ideologue
The United States has imposed sanctions on 14 Ukrainian separatists and Russians, including an idealogue who has heavily influenced the Kremlin.
Political scientist Alexander Dugin is an extreme Russian nationalist closely associated with the Ukraine conflict.
The US said it was cutting business ties and freezing the assets of him and others who had destabilised the situation in the east of the country.
A ceasefire, albeit not fully observed, has been in place for a month.
Russia said it found the new wave of sanctions "difficult to understand".
"We categorically do not see any link between what has recently been happening in south-eastern Ukraine and these sorts of actions," Deputy Foreign Minister Sergei Ryabkov told the news agency Interfax.
President Barack Obama and European leaders have used sanctions as its main form of retaliation for Russia's annexation of Crimea and backing of separatists groups in eastern Ukraine.
"If Russia continues to support destabilising activity in Ukraine and violate the Minsk agreements and implementation plan, the already substantial costs it faces will continue to rise," said Adam Szubin of the US treasury department.
New US targets
- Alexander Dugin is the founder of Russia's anti-European Eurasian movement, and his views are thought to be popular among the hawkish Russian elite
- the youth wing of the Eurasian organisation is the Eurasian Youth Union, which is banned in Ukraine
- Alexander Khodakovsky was a commander of the SBU secret service in Ukraine but defected and is now head of security for the pro-Russian rebels in Donetsk
- Ukraine is seeking the extradition of Mykola Azarov, PM under deposed President Yanukovych, on allegations of embezzlement
- Former deputy PM Serhiy Arbuzov was also head of the central bank
- His minister of health was Raisa Bohatyriova
Among those targeted for sanctions is former prime minister Mykola Azarov and two other top Ukrainian officials in former President Viktor Yanukovych's inner circle, for "misappropriation of Ukrainian state assets".
Also included are five officials in the self-proclaimed Luhansk and Donetsk's people's republics and the leaders of Eurasian Youth Union, including Alexander Dugin.
Mr Dugin, a prominent Russian ultra-nationalist philosopher, has called on President Vladimir Putin to intervene militarily in eastern Ukraine "to save Russia's moral authority".
The US says the Eurasian Youth Union has "recruited individuals with military and combat experience to fight on behalf of the self-proclaimed DPR and has stated that it has a covert presence in Ukraine".
A Russian bank operating in Crimea, now the largest banking network in the region, has also seen its assets blocked by the US.
In a separate development, the US is preparing to send more non-lethal aid to Ukraine, including unarmed drones, an unnamed official told US media on Wednesday.