BEIJING (Yonhap) -- Trade between North Korea and its economic lifeline, China, grew 4.6 percent on-year in February, Chinese customs data showed Wednesday, despite tensions over the launch of a long-range rocket following the North's fourth nuclear test.

Bilateral trade volume stood at $323 million last month, according to the data. China's imports of North Korean goods gained 2.48 percent on year to $162 million and its exports to the North rose 6.91 percent to $161 million.

Compared with January, however, bilateral trade fell about 15 percent.

The U.N. Security Council imposed tougher sanctions on North Korea earlier this month to punish it for the Jan. 6 nuclear test and Feb. 7 launch of a long-range rocket, both of which violated previous U.N. resolutions.

China, which accounts for nearly 90 percent of North Korea's external trade, has vowed to fully implement the new U.N. sanctions on North Korea.

But, China has also made it clear that sanctions should not affect the normal trade between the two nations.