Japan's trade surplus plunged 29 percent in May from a year earlier as imports outpaced exports, following a 10.3 percent surge the previous month.

An expansion in imported items, including crude oil and personal computers, overwhelmed big rises in exports of information-technology-related products, the Finance Ministry said Wednesday.

The politically sensitive trade surplus with the United States also fell, by 9.8 percent, following three straight months of year-on-year rise.