The Seoul-financed Korea Institute for National Unification said in a report that since late 2015, the North has been bolstering border controls and installing high-tension electric fencing along the Tumen River that forms the border with China.
North Korea's multiple missile tests in recent months, culminating with its first-ever successful launch last week of an intercontinental ballistic missile capable of reaching Alaska, has alarmed the worldwide community and presented Trump's first major foreign policy test.
President Trump and administration officials have grown increasingly irritated that China has not done more to rein in North Korea's nuclear and missiles programs, despite public pressure from the U.S.
That increase "cannot be used as evidence questioning China's seriousness in fulfilling UNSC resolutions", Huang said.More news: Reps order recall of suspended NHIS boss
Exports to North Korea rose 29.1 percent to $1.67 billion during the period, the data showed. He has been urging the UN Security Council to impose a "complete economic embargo" requiring all member nations to cut off all finance and trade with the North, with a few limited humanitarian exceptions. "It has nothing to do with creating income for DPRK nuclear programmes, so it is not on the sanctions list", Geng told a regular news briefing.
"I'm introducing a legislation that will create a global embargo against North Korea to shut off access to the United States financial systems and the systems and sources of trade that wish to continue to do business with North Korea", Gardner said in a statement.
"If Trump were to give up on Chinese support in terms of containing North Korea, then there's a risk of increased trade tensions between the USA and China, which could negatively impact China's overall export performance", said Julian Evans-Pritchard, China economist at Capital Economics.
Trump acknowledged as much at a July 12 press availability held aboard Air Force One on the way to France to celebrate Bastille Day. He called out the "nearly 40%" increase in trade in the first three months of the year on Twitter last week.