North Korea's top envoy to the United Nations has sent a letter to UN Secretary-General Antonio Guterres to criticize the United States' recent seizure of its cargo ship suspected of violating international sanctions, Pyongyang's state media said Saturday.

In the letter sent Friday, Kim Song called the seizure an "unlawful, outrageous and sovereignty-infringing" act, which he said indicated the US is "indeed a gangster country," according to the North's official Korean Central News Agency.

The US Justice Department said on May 9 that it has seized the 17,061-ton Wise Honest suspected of transferring coal and machinery in violation of the sanctions regime, in the first such direct seizure by American authorities.

"Recently, the US committed an unlawful and outrageous act of taking the DPRK's cargo ship to Samoa, linking the ship to the violation of the American domestic law, and this act of dispossession has clearly indicated that the United States is indeed a gangster country that does not care at all about international laws," the North's permanent representative at the UN wrote in the letter.

DPRK stands for the North's official name, the Democratic People's Republic of Korea.

"Moreover, the United States committed a sovereignty-infringing act of flagrantly violating the UN Charter by dispossessing the cargo ship where the DPRK's sovereignty is fully exercised," the envoy added.

The seizure added to uncertainties over the prospects for the resumption of stalled nuclear talks between Washington and Pyongyang.

Their negotiations have hit an impasse since the second summit between US President Donald Trump and North Korean leader Kim Jong-un in Hanoi in February due to a failure to bridge gaps over the scope of Pyongyang's denuclearization and Washington's sanctions relief.

(Yonhap)