"North Korea must be held accountable for its risky and destabilising actions", said Senator Robert Portman".
Though Trump took a more conciliatory tone on the North Korea issue and China's role at a meeting with Chinese President Xi Jinping on Saturday, Beijing has begun taking a harder rhetorical line with Washington in the past few days.
"China customs have all along fully, accurately, conscientiously and strictly enforced relevant Security Council resolutions", Huang declares.
About 90 percent of North Korea's exports go to China, and coal has been the single biggest export item.
The Trump administration has been calling on Beijing to use its economic leverage over its errant neighbor to make the Kim Jong Un regime stop firing off missiles and bellicose threats.
The Chinese customs department released figures that showed significant growth in overall bilateral trade in the first six months of the year.
Numbers showing an increase are not evidence that China is failing to enforce United Nations resolutions, with imports from North Korea falling every month since March, Huang added. The country even suspended imports of coal back in February.More news: Lonzo Ball Named MVP, Lakers Win Summer League
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He pointed to a 13.2 percent drop in imports from North Korea in the same period as an example of the pressure, adding that there have been sharp decreases every month since March.
I also support increasing sanctions against China and Chinese companies that support the Kim regime.
The five countries should discuss what incentives they can offer to North Korea in case Pyongyang freezes its nuclear facilities and dismantles them in a verifiable manner, he said.
At the same time, iron ore imports have surged between January and May to $74.4 million compared to $24 million over the same period past year.
Trade between China and North Korea has declined in both 2015 and 2016, a senior government-backed academic said in a front-page comment in the overseas edition of the official People's Daily on Wednesday.
President Donald Trump and his top aides have signaled growing impatience with China over North Korea, especially since Pyongyang last week test-launched its first intercontinental ballistic missile, which experts say could put all of Alaska in range for the first time.
The official further noted the Philippines' robust relationship with the US, Russia, China Japan as well as a major trading partner of South Korea.