WASHINGTON - The United States on Wednesday slapped sanctions on two shipping companies of the Democratic People's Republic of Korea (DPRK) for their attempt to import arms and related material from Cuba last year.

Chongchongang Shipping Company and Ocean Maritime Management Company were targeted for using "deliberate and evasive methods" to conceal the cargo aboard Chong Chon Gang, a DPRK-flagged cargo vessel, the Department of Treasury said in a statement.

It said the shipment included various components of surface-to-air missile systems and launchers, MiG-21 jet fighters parts and engines, shell casings, rocket propelled projectiles and other ammunition.

The cargo was falsely declared to be sugar and spare plastic sacks and was camouflaged and hidden under 200,000 bags of sugar when the vessel entered the Panama Canal in July last year, the agency said.

"North Korea uses companies like Chongchongang Shipping and Ocean Maritime Management to engage in arms trading in violation of US and international sanctions," said David Cohen, under secretary of Treasury for terrorism and financial intelligence.

"The Chong Chon Gang episode, in which the DPRK tried to hide an arms shipment under tons of sugar, is a perfect example of North Korea's deceptive activity, and precisely the sort of conduct that we are committed to disrupting," he added.

Chong Chon Gang, operated by the government-owned Chongchongang Shipping Company, and 17 other vessels in which the blacklisted shipping companies have an interest, were identified as "blocked property" by the Treasury.

The Treasury's move freezes all assets of the entities targeted and bars American citizens from making transactions with them.

Glyn Davies, US special representative for DPRK policy, on Wednesday accused Pyongyang of continuing to pursue nuclear weapons and ballistic missiles, saying the move poses "a growing threat" to the US and its allies in the region as well as the global nonproliferation regime.

"We seek a solution to the North Korea nuclear challenge through peaceful, persistent, multilateral diplomacy," he told a Senate panel.