U.S. President Barack Obama imposed fresh sanctions on North Korea on Wednesday, further tightening the screws on Pyongyang for its nuclear and missile tests, including the blacklisting of anyone assisting the North over its labor and mineral exports.

"I have now determined that the government of North Korea's continuing pursuit of its nuclear and missile programs ... increasingly imperils the United States and its allies," Obama said in the new executive order. "The order addresses those actions and takes additional steps."

Obama said the new measures target the North's government, not its people, and block the property and interests in property of the government in Pyongyang, its ruling Workers' Party and "any person" helping the regime with its nuclear and missile programs, cyber-attacks, human rights abuses and other illicit activities.

The order carries out both the new U.N. Security Council sanctions resolution and the recently enacted U.S. sanctions law against Pyongyang, and is largely aimed at choking off sources of cash for the regime, including sanctioning exports of the North's mineral resources.

But it also has a new measure, such as the "blocking of the property and interest in property of any person found "to have engaged in, facilitated, or been responsible for the exportation of workers from North Korea, including exportation to generate revenue for the government of North Korea or the Workers' Party."

Labor exports have increasingly been an important source of foreign money for Pyongyang.

Marzuki Darusman, the U.N. special rapporteur on North Korea's human rights situation, said in a report to the U.N. General Assembly last year that Pyongyang earns between $1.2 billion and $2.3 billion per year from such worker exploitation.

About 50,000 North Koreans are believed to be toiling overseas, mainly in the mining, logging, textile and construction industries, the report said. Such workers earn on average $120-150 per month while employers pay significantly higher amounts to the North's government, it said.

They are also forced to work sometimes up to 20 hours per day, with only one or two rest days per month, and health and safety measures are often inadequate, the report said. Workers are given insufficient daily food rations, it said.

"Today, the president issued an executive order imposing robust new sanctions on North Korea," White House press secretary Josh Earnest said. "These actions are consistent with our longstanding commitment to apply sustained pressure on the North Korean regime."

The U.S. and the global community will not tolerate North Korea's illicit nuclear and ballistic missile activities, and we will continue to impose costs on North Korea until it comes into compliance with its international obligations, Earnest said.

Under the executive order, the Treasury Department blacklisted two North Korean officials, 15 companies and 30 vessels, largely in accordance with the U.N. Security Council sanctions. But North Korean leader Kim Jong-un was not among them.

The two sanctioned officials are Ri Won-ho and Jo Yong-chol, officials of the North's Ministry of State Security stationed in Egypt and Syria, respectively. Both were accused of facilitating the North's Mining Development Trading Corporation's business in the two countries, the department said.

"President Obama's new Executive Order and the Treasury's simultaneous designations reflect the United States' commitment to holding North Korea accountable for its destabilizing actions," said Adam J. Szubin, acting under secretary for terrorism and financial intelligence.

"These actions implement both the unanimous UNSCR approved earlier this month as well as recent bipartisan sanctions legislation on North Korea. We will work closely with our international partners to continue in a strong and unambiguous way to pressure North Korea to abandon its illicit nuclear and ballistic missile programs," he said. (Yonhap)