The U.S. Department of Treasury imposed a fresh round of sanctions Tuesday against six North Korean bankers and three shipping companies for their links to illegal arms trafficking and financing operations. The sanctions list included Pyongyang's Strategic Rocket Force, which U.S. officials had earlier targeted for conducting several ballistic missile launches in 2014.

The list was aimed at preventing North Korea from accessing the U.S. financial system and to maintain the effectiveness of the existing sanctions, reports said. And, the treasury department said that the rocket command “materially contributed” to developing the country’s ballistic missiles program.

“As a result of today’s action, any property or interest in property of the designated persons in the possession of U.S. persons or within U.S. jurisdiction must be frozen," the treasury department said, in a statement released Tuesday.

Five representatives from the Tanchon Commercial Bank, which was placed under sanctions by the U.S. in 2005, were targeted in the latest round of sanctions by the U.S. Two of them -- Jang Bom Su and Jon Myong Guk -- were based in Syria, the Wall Street Journal reported Tuesday. Two other representatives based in Vietnam were identified as Choe Song Il and Kim Jung Jong. The fifth representative was identified as Koe Tae Hun who, along with Jon, reportedly helped move funds linked to the Korea Mining Development Trading Corp. The mining company was also placed under sanctions in 2005.

Kim Kyong Nam, a Russia-based representative for North Korea’s Foreign Trade Bank, was also named in the sanctions list, the Journal reported. The bank faced sanctions in 2013.

Shipping companies, Haejin Ship Management Co., Pyongjin Ship Management Co. and Yongjin Ship Management Co. -- which are owned by Ocean Maritime Management Co. -- were also targeted. The U.S. treasury accused Ocean Maritime, which faced sanctions in 2014 from the United Nations for smuggling Soviet-era arms, including two MiG-21 fighter planes, of using aliases and fronts to operate.

“North Korea threatens international peace and security by expanding its nuclear program and continuing its proliferation of weapons of mass destruction and conventional weapons,” Adam J. Szubin, the acting under secretary for terrorism and financial intelligence, said, in the statement from the treasury department, adding: “Treasury is committed to exposing North Korea’s global proliferation network and excluding these facilitators from the international financial system.”

North Korea has been the subject of U.S. sanctions aimed mainly at discouraging the former's ambitions to become a nuclear power. In September, Pyongyang accused the U.S. of trying to “suffocate” North Korea with its sanctions, which it said were a result of an "inveterate animosity and hostile policy" toward the North Korean government.