NEW DELHI—The United States and several allies have signaled a renewed focus on the Pacific Island with fresh visits and diplomatic engagements this month, but a lot more needs to be done to mitigate the Chinese regime’s influence in the region, according to experts. Beijing has over the years steadily expanded its economic and political footprint in the South Pacific, a region that consists of 14 sovereign island nations and seven territories with a cumulative population of 13 million. But as Washington and allies step up their commitment to the Indo-Pacific region to counter the Chinese regime’s growing assertiveness there, they have also set their sights on the Pacific Islands. In a Feb. 11 meeting in Melbourne, Australia, of foreign ministers of the informal QUAD grouping of the United States, Australia, Japan, and India, the countries agreed to enhance their cooperation to ensure the region is “free of coercion,” a …