North Korea's trade with its economic lifeline China fell 2.1 percent on year to US$2.89 billion in the first six months of this year, data compiled by South Korea's government trade agency showed Monday, in another sign that strained political ties between the two nations have affected their economic relations.

During the six-month period, North Korea's exports to China declined 3.9 percent to $1.31 billion and imports slipped 0.6 percent to $1.58 billion, according to the data provided by the Beijing unit of South's Korea Trade and Investment Promotion Agency (KOTRA).

There were no shipments of crude oil from China to North Korea from January to June, the data showed.

But a diplomatic source with knowledge of the matter cautioned against reading too much into the official trade figures because China has provided crude oil to North Korea in the form of grant aid and such shipments were not recorded on paper.

"Despite the six-month absence of oil shipments, the scale of North Korea's decline in imports is minimal," the source said on condition of anonymity.

Meanwhile, North Korea's exports of rare earth to China jumped 153.7 percent on year during the January-June period, the data showed, without providing the value of the exports. (Yonhap)