June 1 (Bloomberg) -- U.S. Defense Secretary Robert Gates said North Korea may be preparing to conduct its second long- range ballistic missile test since April, following last month’s detonation of a nuclear device.

“We have seen some signs that they may be doing something with another Taepodong-2 missile,” Gates said at a press conference in Manila with Philippines Defense Secretary Gilbert Teodoro. “But at this point it’s not clear what they’re going to do.”

The comments followed a Yonhap News report that China suspended government exchanges with North Korea after its May 25 nuclear test and firing of six short-range missiles last week. The report, if confirmed, would be the strongest reaction yet by North Korea’s biggest trading partner.

China agreed last week with the U.S., Japan and Russia to work toward a United Nations Security Council resolution censuring the regime. Gates, in Asia for a week-long tour, said on May 29 that “based on what the Chinese government has said publicly, they’re clearly pretty unhappy.”

Gates flew in from Singapore, where he attended an annual Asian security conference and held talks with his Japanese and South Korean counterparts on North Korea’s nuclear test. He met with Teodoro to discuss a counter-terrorism training program for the Philippine armed forces, under which 500 to 600 U.S. troops provide tactical training and advice on delivering humanitarian aid to communities affected by terrorism.

Suspending Visits

China has halted plans to send officials to North Korea and won’t accept visits from there either, Yonhap News said today, citing unidentified diplomatic sources in Beijing. China’s foreign ministry didn’t respond to a faxed request for comment. South Korean government spokesman Lim Jung Taek said he couldn’t confirm or deny the story.

Even as North Korea has defied the international community, China has emphasized its bond between the two countries, designating 2009 a “Year of Friendship” to mark 60 years of ties.

Shen Dingli, deputy dean of the Institute of International Affairs at Fudan University, said it was “impossible” China would halt exchanges.

“A communist country would not boycott a communist country,” Shen said. “They are our allies.”

China accounts for almost three-fourths of North Korea’s foreign trade, and can cut off shipments to the impoverished country of food, fuel and luxury goods.

Recriminations

The latest round of recriminations began when North Korea launched a three-stage rocket on April 5, calling it a successful satellite launch. The U.S., South Korea and Japan said it was a Taepodong-2 ballistic missile, which theoretically can reach Alaska. The UN condemned the test, prompting Kim’s regime to pull out of six-nation talks aimed at persuading North Korea to give up its nuclear weapons program.

South Korea responded to the atomic explosion by joining a U.S.-led initiative to halt shipments of weapons of mass destruction. The North then warned that any move to seize its ships would be met with military retaliation, and also fired six short-range missiles in a show of defiance.

Gates said May 30 that the communist regime would be held “fully accountable” for the consequences of transferring nuclear weapons or material to “states or non-state entities.”

Yellow Sea

North Korea’s military ordered ships in the Yellow Sea and units guarding the country’s coast to double their ammunition stockpiles, Yonhap News reported today, citing a South Korean government official it didn’t identify. The North is also planning to launch a long-distance ballistic missile as early as this month, Yonhap said over the weekend.

South Korean President Lee Myung Bak today called on regional leaders to help thwart North Korea’s nuclear ambitions, saying they were “harmful to the peace and security of east Asia.” He is hosting a summit of the Association of Southeast Asian Nations in Jeju island.

Asean leaders also voiced their concerns over North Korea’s actions, South Korean presidential spokesman Lee Dong Kwan told reporters today in Jeju, at the end of the first day of the summit.

“The leaders were nearly united with one voice, saying that North Korea’s actions were harmful to the stability of not only the Korean peninsula, but also the east Asian region, and that six-party talks must be resumed soon and the matter resolved through dialogue,” the spokesman said.

South Korea and Asean will release separate statements tomorrow at the end of the two-day summit, condemning North Korea’s nuclear test and urging North Korea to return to talks, he said.

To contact the reporters on this story: Viola Gienger in Manila at vgienger@bloomberg.net; Heejin Koo in Jeju at hjkoo@bloomberg.net.

Last Updated: June 1, 2009 06:52 EDT