A stevedore works at Qingdao port in Shandong province, July 1, 2015. [Photo/IC]

BEIJING - China's export growth in yuan-denominated terms slowed to 1.2 percent year on year in May from 4.1 percent in April, customs data showed Wednesday.

Imports grew 5.1 percent, significantly rebounding from a 5.7-percent decline in April, according to figures from the General Administration of Customs (GAC).

Trade surplus last month was 324.8 billion yuan ($50 billion), up from April's 298 billion yuan.

Foreign trade increased 2.8 percent year on year to about 2 trillion yuan in May, while for the first five months combined slipped 3.2 percent to nearly 9.2 trillion yuan, recovering from a 4.8-percent decline for the January-April period.

In the five months, exports dropped 1.8 percent year on year and imports went down 5 percent, leading to a trade surplus of 1.4 trillion yuan.

A leading index for export outlook dropped by 0.7 points to 33.1 points in May, signaling growing pressure on export growth in the third quarter of 2016, said a GAC statement.

Trade with the European Union, China's largest trading partner, climbed 2 percent year on year in the first five months.

Trade with the United States and ASEAN, China's second- and third-largest trading partners, declined 5.2 percent and 1.6 percent, respectively.

Trade with Japan, China's fifth largest trading partner, edged down 0.3 percent.

The GAC said imports of iron ore, crude oil and product oil "notably recovered" in the five months -- up 9.1 percent, 16.5 percent and 4.5 percent, respectively.

However, automobile imports fell 12.8 percent. Plastics and steel imports also posted declines.