Tang Dagang, director of the Vehicle Emission Control Center, a policy research group also affiliated with the ministry, said pressure increased last year to tighten diesel fuel standards after the State Council, or cabinet, announced stricter air-quality rules.

WSJ: China's Pollution Fight Faces Resistance

The U.S. in recent months has put increased pressure on Pakistan to clamp down on insurgent groups, especially the Taliban-affiliated Haqqani network.

WSJ: Attacks Point to New Afghan Conflict