The Kremlin said on Tuesday that U.S. allegations that Russia and China are helping North Korea to dodge sanctions were "absolutely unfounded".
Earlier on Tuesday, U.S. Defense Secretary Lloyd Austin said in Seoul that he was concerned that China and Russia were helping North Korea to expand its military capabilities by enabling it to evade United Nations sanctions.
The Kremlin said on Tuesday that Russia was acting in its own interests when asked about a probe by the United States into alleged violations of Western oil sanctions on Moscow.
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Kremlin spokesman Dmitry Peskov also told a daily conference call with reporters that President Vladimir Putin would hold a meeting on the fuel and energy complex later on Tuesday.
The U.S. Treasury Department has sent notices to ship management companies requesting information about 100 vessels it suspects of violating Western sanctions on Russian oil, according to a source who has seen the documents.