Donald Trump will urge Xi Jinping to make good on his commitments to pressure North Korea when he visits China next month, a senior White House official said on Monday, stepping up a strategy to have Beijing help rein in Pyongyang. Isolating North Korea further over its nuclear and ballistic missile tests is a key goal for Trump on what will be his longest foreign trip to date. Trump will call on Xi to fully implement UN Security Council resolutions against Pyongyang and take other steps to pressure North Korea. China, North Korea’s sole major ally, accounts for more than 90% of trade with the isolated country, according to Reuters. China has said it will strictly enforce UN Security Council sanctions banning imports of coal, textiles and seafood, while cutting off oil shipments to the North. But a senior White House official who briefed reporters ahead of Trump’s trip said China needs to do more to comply with UN Security Council resolutions.