The U.S. Treasury has imposed fresh sanctions against Russian actors in connection with the Kremlin's aggressive cyber attacks.

The additional sanctions have been made to "disrupt Russian efforts to circumvent our sanctions" said U.S. Treasury Secretary, Steven Mnuchin, Sky News reported.

"Today's action against these deceptive actors is critical to ensure that the public is aware of the tactics undertaken by designated parties and that these actors remain blocked from the U.S. financial system," Mr Mnuchin added.

The two newly sanctioned people and firms join three other individuals and five businesses that were accused in June of providing material and technological support to Russia's Federal Security Service (FSB).

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One of the newly proscribed businesses, Vela-Marine, is accused of procuring equipment for the previously sanctioned Divetechnoservices which worked on the Kremlin's programme to interfere with subsea cables.

At the time of the sanctions in June, Mr Mnuchin said the U.S. was "engaged in an ongoing effort to counter malicious actors working at the behest of the Russian Federation and its military and intelligence units to increase Russia's offensive cyber capabilities.

"The entities designated today have directly contributed to improving Russia's cyber and underwater capabilities through their work with the FSB and therefore jeopardise the safety and security of the United States and our allies."

All of the property and interests in property held by the sanctioned individuals and the businesses will be blocked, and people in the U.S. will be prohibited from engaging in transactions with them.

The Kremlin continues to deny that it has engaged in any offensive cyber acts at all.

The two businesses named are Vela-Marine and Lacno, and the individuals are Marina Tsareva and Anton Nagibin, who are accused of acting for or on behalf of Divetechnoservices to help the company circumvent U.S. sanctions.

They are issued on the same day that Microsoft reported it had disrupted an attempt by Russian hackers to interfere in the U.S. midterms, although these are not believed to be related to the sanctions.

A dozen members of the GRU who were previously involved in attempts to interfere in the 2016 U.S. election were named in a legal indictment in July.