Chinese Premier Li Keqiang will offer the leaders of central and eastern Europe on Saturday expanded business ties at a summit in Sofia while seeking to reassure the EU that Beijing is not trying to divide the continent. Li, whose attendance at the seventh such “16+1” summit coincides with an escalating trade war between China and the United States, will also try to dispel growing doubts among some participants about the value of the annual meetings. China has promised billions for development projects in the region as part of its Belt and Road strategy to carve out new export markets,...