The United States on Friday imposed fresh sanctions over North Korea's missile launches, including on two Russian banks, after Russia and China blocked action by the UN Security Council.
The Treasury Department said it was freezing any US assets and criminalizing transactions with the Far Eastern Bank and Bank Sputnik, Russian institutions accused of working with North Korea.
It also targeted Jong Yong Nam, alleged to be working out of Moscow-allied Belarus for North Korea's weapons research body, and a trading company affiliated with state carrier Air Koryo, which is already under sanctions.
Senior Treasury official Brian Nelson said the banks were targeted as they "knowingly provided significant financial services" to the North, formally known as the Democratic People's Republic of Korea.
"The United States will continue to implement and enforce existing sanctions while urging the DPRK to return to a diplomatic path and abandon its pursuit of weapons of mass destruction and ballistic missiles," he said in a statement.
The United States and South Korea have said that North Korea tested three rockets, including an intercontinental ballistic missile, on Wednesday and that it could be preparing its first nuclear test since 2017.
The United States on Thursday forced a vote at the Security Council on toughening sanctions, saying that North Korea had brazenly violated a unanimous 2017 resolution that warned of consequences for further tests.
But Russia, whose relations with the West have sharply deteriorated over the Ukraine war, and China vetoed the US-drafted resolution, saying that sanctions would heighten tensions.
The US ambassador to the United Nations, Linda Thomas-Greenfield, accused Beijing and Moscow of emboldening North Korea and said the United States would take unilateral measures against Pyongyang.