The United States on Thursday, March 7 froze the assets of three North Korean citizens who have links to Pyongyang's main arms dealer, after the UN Security Council voted to tighten financial restrictions on the reclusive country, Reuters reported.

The UN Security Council resolution on Thursday also vowed to crack down on Pyongyang's attempts to ship and receive banned cargo in breach of sanctions, in response to North Korea's test of a nuclear weapon for the third time in February.

The U.S. Treasury Department designated for sanctions a North Korean who worked in Beijing, China as a representative of the Tanchon Commercial Bank, the financial arm of North Korea's premier arms dealer and weapons exporter. Two others targeted are the direct representatives of the arms dealer itself, called the Korea Mining Development Corporation (KOMID), and are based in Dalian, China.

The designations freeze the assets of those affected and prohibit U.S. citizens from doing business with them.

"These individuals are important actors within North Korea's proliferation network who have been working to gain access to international markets," David Cohen, Treasury undersecretary for terrorism and financial intelligence, said in a statement.

KOMID has offices around the world and helps move weapons to the North Korean government, the Treasury said.

The Security Council called on the United Nations' 193 member states to block any financial services or monetary transfers that could contribute to North Korea's weapons programs.