The US has called North Korea's move to expel American weapons experts working on disabling its main nuclear plant "a step backward".
"It's a step backward," Robert Wood, a US state department spokesman, said on Wednesday. "The North is going to have to deal with the consequences of such decisions. And they just bring upon themselves further isolation from the international community."
Wood said four officials monitoring the North's disablement of its Yongbyon nuclear plant were now preparing to leave.
The expulsions are the latest in a flurry of responses by the North following the UN Security Council's condemnation of its rocket launch this month.
North Korea accused the UN of double standards and declared that it would restart its nuclear activities on Wednesday.
The North also rejected the UN statement, pulled out of six-party denuclearization talks and expelled weapons inspectors from the UN nuclear watchdog, the International Atomic Energy Agency (IAEA).
'Double standards'
Pak Tok Hun, the North Korean ambassador to the United Nations, told Al Jazeera that the UN was not being fair.
"There are lot of countries that launched their satellite in the last few years including the United States and Japan - which launched satellites more than 100 times - but this was not dealt with by the security council.
"Why does the Security Council deal with the issue in the case of my country? This is selectivity, double standards, it's not fair. We cannot accept that, we made it clear," he said, warning that Pyongyang would respond by taking the "appropriate strong measures".
The UN Security Council statement issued on Monday condemned the North's April 5 rocket launch, saying it violated a resolution banning Pyongyang from conducting missile-related activities.
Pyongyang says the launch placed a satellite into orbit, and has defended what it says is its sovereign right to a space program.
But the US military says no satellite has been detected after the rocket's upper stage and its payload crashed into the Pacific ocean.
It says the launch was a cover for a long-range ballistic missile test.
PHOTO CAPTION
A TV-video grab from April 5 shows the launch of a rocket from an undisclosed location in North Korea.
Al-Jazeera