The shadow of the Iran war is threatening to disrupt President Donald Trump's summit with Chinese leader XI JINPING. The US is seeking to resolve the standoff over the Strait of Hormuz, where China imports significant amounts of oil from Iran. The White House has been trying to enlist allies and global rivals to persuade Iran to reopen the vital waterway. China has also made its stance clear on the nuclear issue, affirming Iran's "legitimate right to the peaceful use of nuclear energy". The meeting sets China up in a strong position before talks with President Trump, and could provide leverage for Beijing to make its own demands. Beijing has also ordered Chinese companies not to comply with U.S. sanctions over alleged purchases of Iranian oil, a move seen as a show of defiance ahead of Trump's visit.