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Vice President Dick Cheney (search) challenged Asian powers Thursday to do more to contain North Korea's nuclear program, saying that letting it grow unchecked could spark a new arms race in the region and create a weapons bazaar for terrorists.

"We must see this undertaking through to its conclusion," Cheney told a university audience in Shanghai, China. "Time is not necessarily on our side." He expressed clear frustration with the current diplomatic stalemate before flying to South Korea, his last stop of a weeklong Asia trip.

The speech was carried by China's state television without deletions or blackouts, which U.S. officials took as an encouraging sign of change.

Cheney praised China for setting up six-way talks to persuade North Korea to dismantle its nuclear program, but he prodded Chinese leaders to be more aggressive in bringing pressure to bear on Pyongyang.

The six-way talks include the United States, China, Russia, Japan and the two Koreas.

"We'll do our level best to achieve this objective through diplomatic means, and through negotiations. But it is important that we make progress in this area," Cheney said.

He suggested that North Korea represented a double threat — it could stock its own nuclear arsenal and sell weapons to the highest bidder, including Al Qaeda and other terror organizations.

"The people of Asia are particularly vulnerable to the threats of (weapons) proliferation," Cheney said. "Many countries that have the means to develop the deadliest weapons have refrained from doing so."

But he said a continued North Korean nuclear threat could persuade other powers in the region to develop their own nuclear weapons, triggering a new arms race across the region "and the likelihood that one day those weapons would be used."

Cheney said recent information gleaned from a top former Pakistani nuclear scientist provided compelling evidence that Pyongyang has an active atomic weapons program.

The reclusive communist government "must understand that no one in the region wants them to develop those weapons," Cheney said.

During Cheney's Asia trip, citizens from all three countries he visited — Japan, China and South Korea — were seized by militants in Iraq. Three Japanese hostages were released Thursday. The South Korean and Chinese hostages were freed earlier.

Cheney has engaged in unusually blunt talk in his travels, urging allies with troops in Iraq not to bow to pressure from militants and telling Chinese leaders that U.S. defensive military sales to Taiwan are largely a response to their own military buildup on the Taiwan Strait.

In remarks at Shanghai's Fudan University (search), almost exactly 20 years after President Reagan spoke on the campus, Cheney praised China's economic advances but pointedly suggested they be coupled with "full freedom of religion, speech, assembly and conscience."

"Prosperous societies ... come to understand that clothing, cars and cell phones do not enrich the soul," he said.

The vice president arrived in South Korea on Thursday shortly before polls closed in parliamentary elections. A liberal party loyal to South Korea's impeached president won the most seats.

The win by the Uri party could result in the crafting of a foreign policy more independent of the United States, South Korea's traditional ally, and the forging of closer ties with the North.

Cheney came seeking South Korea's support on the North Korea nuclear issue and its commitment to a promise to send more than 3,000 troops to Iraq.

He was meeting with South Korea's acting president, Prime Minister Goh Kun (search), and visiting U.S. troops stationed in Seoul before returning Friday to Washington.

In a question-and-answer period, one student asked Cheney to describe his relationship with President Bush, given that he was often described as "the most powerful vice president in history."

"That's not a question I had anticipated," Cheney said to laughter.

He said the role of the U.S. vice president had evolved over recent years into one of more responsibility. But he said that the vice president's actual authority, other than his constitutional duty to cast tie-breaking votes in the Senate, was "based strictly upon your relationship with the president."

"I've been fortunate," he said.