Pre-emptive attacks on North Korea's nuclear facilities would trigger a "total war," Pyongyang warned Thursday after U.S. Secretary of Defense Donald H. Rumsfeld labeled the North's government a "terrorist regime."

The harsh rhetoric came a day after North Korea said it was putting the operation of its nuclear facilities on a "normal footing," triggering fears it was about to produce weapons materials. South Korea said it had no sign that the North had reactivated its nuclear facilities, but officials said the North's statements were unclear and that they were trying to clear them up.

"When the U.S. makes a surprise attack on our peaceful facilities, it will spark off a total war," the state-run newspaper Rodong Sinmun said in a commentary carried by North Korea's official news agency, KCNA.

Ri Pyong Gap, a spokesman and deputy director at the North's Foreign Ministry, told London's The Guardian newspaper that the impoverished country was entitled to launch a pre-emptive strike against the United States.

"The United States says that after Iraq, we are next," the paper quoted Ri as saying, "but we have our own countermeasures. Pre-emptive attacks are not the exclusive right of the U.S."

It's customary of the North to launch saber-rattling invectives against Washington when it has a dispute to settle.

Although Washington has repeatedly denied it plans to invade North Korea, Rumsfeld said restarting the nuclear program would give the North a troubling option -- making nuclear weapons for itself or selling them to any other country.

"That is something the world has to take very seriously," he said late Wednesday. "It's a regime that is a terrorist regime. It's a regime that has been involved in things that are harmful to other countries."

In an English-language statement, North Korea said Wednesday that it "is now putting the operation of its nuclear facilities for the production of electricity on a normal footing after their restart."

However, a Korean-language statement monitored by South Korea's Yonhap news agency referred only to "our process to restart nuclear facilities for generating electricity and normalize their operation."

Both North Korean statements were carried on KCNA, the North's official news agency.

Ths statements left it unclear how far North Korea has proceeded in reactivating its nuclear facilities, which include a 5-megawatt nuclear reactor, a storage building for 8,000 spent fuel rods and a plant where those rods could be reprocessed to yield enough plutonium for four or five bombs in a matter of months.

Last week, U.S. officials said spy satellites detected covered trucks apparently taking on cargo near the storage building.

The International Atomic Energy Agency, the Vienna-based U.N. nuclear monitoring agency, said it couldn't confirm any new nuclear activities because its inspectors were sent out of the country in December.

The most immediate step the North could take is likely to be restarting the 5-megawatt reactor, which can produce more spent fuel rods, South Korean officials said.

"We are trying various channels to confirm what it means," said an official at the South Korean Foreign Ministry, who spoke on condition of anonymity. "At this moment, we have no information to confirm that North Korea has reactivated its nuclear facilities, that is the reactor and other key facilities."

North Korea said in December that it was reactivating its facilities to generate badly needed electricity. But U.S. officials say the amount of electricity that can be produced in the Yongbyon facilities is negligible.

Even as it presses toward war with Iraq, the United States has insisted it wants a peaceful solution in the standoff with North Korea.

President Bush "keeps all of his options open," National Security Adviser Condoleezza Rice said in a television interview. "But he happens to believe that this is a situation with North Korea that can be resolved diplomatically."

Analysts say North Korea, which often accuses the United States of plotting to invade it, is fearful that Washington would turn up pressure on the isolated communist nation if the U.S. military wins a war with Iraq.

The North froze its nuclear facilities in a 1994 energy deal with the United States, but the deal unraveled after U.S. officials said in October that North Korea had admitted embarking on a second, clandestine nuclear program.

Washington and its allies suspended oil shipments as punishment. The North then took steps to restart the nuclear facilities, expelled U.N. monitors and withdrew from a global nuclear arms control treaty.

The U.N. nuclear agency's 35-nation board of governors will meet next Wednesday to discuss the standoff and is almost certain to send the dispute to the U.N. Security Council -- a move that could lead to economic sanctions against Pyongyang.