North Korea slammed the U.S. for allegedly covering up its involvement in the bombing of Russia-owned Nord Stream gas pipelines a year ago, in what an expert called yet another attempt by Pyongyang to garner favor with Moscow.

Washington and its allies are trying to “cover up the traces of their involvement” in bombing the Nord Stream gas system by rejecting Moscow’s appeals for a joint investigation, a director at the DPRK foreign ministry in charge of relations with Russia said in a statement published by Korean Central News Agency (KCNA) on Monday.