Pyongyang's state-controlled news agency KCNA reported the Foreign Affairs Committee of North Korea's Supreme People's Assembly denounced the passage of H.R. 1644, adopted in an overwhelming 419-1 vote last week.
"On May 4, the U.S. House of Representatives adopted the 'Korea Interdiction and Modernization of Sanctions Act,' a measure we strongly condemn and totally reject," the statement read.
The North Korean committee also said the law "undermines the sacred right of sovereignty of the Democratic People's Republic of Korea and violates the rights of North Korean citizens."
The unilateral sanctions also "violate all the principles of the United Nations Charter and international law," according to Pyongyang.
North Korea also warned against stepping up pressure, a measure that would "only accelerate the nuclear deterrent" of the country.
The U.S. sanctions adopted May 4 penalizes exporters of crude oil and prohibits countries from hiring North Korean labor.
Restrictions on crude oil exports to North Korea may already be hurting the country.
The South China Morning Post reported Thursday tour buses in Pyongyang are experiencing difficulties and guides warned visitors vehicles would have to suspend operations "if the sanctions cut off our oil supply."
Scarcity, however, has also been met with adaptation and even improvements, including an increase in the use of electric bicycles and hybrid taxis in Pyongyang, according to the report.
Shortage of material, including asphalt, was also faulted for the condition of roads in the country, which were last built in the 1990s.
But North Koreans sometimes take matters into their own hands, the report states.
Teams of "construction workers were burning wood to melt some solid black substance – likely asphalt – in large iron woks by the roadside, creating heavy black smoke and a stink," the Post's Liu Zhen wrote.