BEIJING, April 26. /TASS/. The Chinese authorities are determined to step up support for Russia amid tightening sanctions against Moscow, Chinese Foreign Ministry Spokesperson Wang Wenbin said on Monday. “We strongly oppose the use of unilateral sanctions. China and Russia maintain relations of comprehensive partnership with each other. China and Russia will support each other in matters of protecting state sovereignty,” he stressed at a regular press briefing commenting on tighter US sanctions against Moscow.