North Korea's ambassador to the UN warned the US on Tuesday that its seizure of a cargo ship could have consequences on the future of relations and stalled nuclear talks. Kim Song said the communist state was watching "every move" by the Trump administration after the detention of the state-owned <em>Wise Honest</em>. "The United States should deliberate and think over the consequences its outrageous acts might have on the future development," Mr Kim said, calling on America to immediately return the ship. Its seizure was an "outright denial" of commitments made by US President Donald Trump to North Korean leader Kim Jong-un to improve relations, the UN envoy said. The US announced on May 9 that it had impounded the <em>Wise Honest</em>, saying it was being used to export North Korean coal in breach of UN sanctions over its nuclear weapons and ballistic missile programmes. It was the first time the US had seized a North Korean vessel after several years of close calls on the high seas in which the country's shippers renamed their vessels, used false flags and turned off their tracking devices to avoid detection. The seizure came amid heightened tension after Pyongyang conducted weapons drills involving short-range missiles, and with nuclear talks deadlocked since the collapse of the Hanoi summit between Mr Trump and Mr Kim this year. The UN ambassador said responsibility for what happened next lay with the US. "We shall watch every move by the United States with regard to these issues," Mr Kim said.