UPDATE 1-U.S. sanctions will not make Russia stop protecting its interests, Russian ambassador says

(Adds quote, details in paragraphs 3-6)

Feb 23 (Reuters) - A new round of U.S. sanctions is an attack on Russia's core interests but Moscow will keep protecting them, the RIA news agency quoted Russian ambassador to the United States Anatoly Antonov as saying on Friday.

The United States earlier imposed extensive sanctions against Russia, targeting more than 500 people and entities to mark the second anniversary of Moscow's invasion of Ukraine and retaliate for the death of Russian opposition leader Alexei Navalny.

"The new illegitimate restrictions are yet another brazen and cynical attempt to interfere in the internal affairs of the Russian Federation," RIA quoted Antonov as saying.

The United States targeted Russia's state-owned National Payment Card System, the operator of the Mir payment system, SPB Bank, owned by SPB Exchange, gold producer Uzhuralzoloto, pipe manufacturer TMK, and major Russian steelmaker Mechel, among others.

The National Payment Card System said that the sanctions would not affect the operation of payment services inside the country.

The U.S. also imposed sanctions on the producer of the Russian luxury Aurus limousine. The Kremlin said on Thursday that Vladimir Putin had given Kim Jong Un an Aurus as a gift because the North Korean leader liked the car when the Russian president showed it to him last year. (Reporting by Reuters)