U.S. Secretary of State Hillary Clinton warned North Korea Thursday that the United Nations Security Council will take further action if Pyongyang goes ahead with a rocket launch, which many believe is a ballistic missile test.

Speaking in Washington after meeting with her counterparts from the Group of Eight leading industrialized nations, Clinton said North Korea can choose between isolation and closer ties with the international community.

“Pyongyang has a clear choice. It can pursue peace and reap the benefits of closer ties with the international community, including the United States. Or it can continue to face pressure and isolation. If Pyongyang goes forward, we will all be back in the Security Council to take further action. And it is regrettable because, as you know, we had worked through an agreement that would have benefited the North Korean people with the provision of food aid. But in the current atmosphere, we would not be able to go forward with that, and other actions that other countries had been considering would also be on hold.”

United Nations Secretary-General Ban Ki-moon has urged North Korea to heed the call of the international community and cancel the upcoming rocket launch.

Mr. Ban spoke Thursday in Geneva, as North Korean engineers prepared to launch a rocket that Pyongyang says will carry a weather satellite into space. Western nations and regional neighbors accuse the North of using the launch as a ploy to test a ballistic missile that could later be fitted with a nuclear warhead.

The U.N. chief repeated warnings that the launch, which is set to take place sometime between Thursday and Monday, will raise tensions in the region. He also said it “clearly” violates a U.N. Security Council resolution aimed at reining in North Korea's nuclear weapons program.

Meanwhile, military forces in South Korea and Japan were on high alert Thursday on what the North says is the first day of a five-day window for the launch.

Plans for a Thursday launch dimmed by mid-day due to cloudy skies, with no sign of new activity at the launch pad outside a cloud-covered Pyongyang.

In Tokyo, Prime Minister Yoshihiko Noda repeated his nation's appeal for Pyongyang to cancel the launch but said Japanese forces are ready to shoot down the rocket if it strays over Japanese territory.

“In case it happens, we are on full alert. Up to the last minute, we urge North Korea to refrain from launching.”

South Korea has also put its forces on heightened alert and threatened to shoot down the rocket if it appears likely to crash into South Korean territory. The Philippines, located near the planned splashdown site of the rocket's first stage, has diverted airline flights and ordered fishermen to avoid the area.

Paek Chang Ho, chief of North Korea's launch command center, told reporters Wednesday that fuel was being loaded into the rocket in one of the final steps before launch. The journalists, including a reporter with VOA's Korean service, were able to view the activity by video, which was fed live to the remote command center.

Earlier this week, Secretary Clinton said the launch has raised doubts about North Korea's claims that it wants to improve ties with its neighbors and the United States.

U.S. officials fear that Pyongyang may be planning to follow the launch with what would be its third underground nuclear weapons test. Satellite intelligence photographs made available to VOA and other news organizations this week show evidence of preparations for such a test.

North Korea's launch plan has derailed a recent agreement with the U.S., under which Pyongyang agreed to suspend its nuclear weapons and missile programs. The U.S. was to have delivered 240,000 tons of badly needed food aid to the North.