SINGAPORE (Reuters) - The United States and its Asian allies could look at tougher responses should diplomacy fail to get North Korea to abandon its nuclear program, officials at a security conference said at the weekend.

U.S. Defense Secretary Robert Gates told his counterparts from South Korea and Japan on Saturday that while diplomacy was preferred, other steps may be considered if it failed.

“Six party talks are the preferred course of diplomacy,” Pentagon press secretary Geoff Morrell said, referring to the now defunct talks among the two Koreas, China, Russia, Japan and the United States to disarm the North.

“But given that the six-party talks haven’t produced the results we’re looking for, Gates also made the point that while we pursue that course, we have to look at other options ... to improve our defenses, if that becomes necessary,” he told Reuters.

A Japanese government official, briefing reporters on Saturday after Gates met Japanese Defense Minister Yasukazu Hamada on the sidelines of the Asian Security Conference in Singapore, said missile defense was one of the topics raised.

“There are two paths we can take against North Korea,” the official quoted Gates as telling Hamada.

“One is the diplomatic effort through six-party talks or the United Nations. The other is for Japan, the U.S. and South Korea to strengthen anti-nuclear proliferation measures. Specifically, that could mean missile defense and other defensive moves against North Korea.”

CONSULTATIONS ABOUT TEST

South Korea on Tuesday joined the Proliferation Security Initiative, an ad hoc alliance of states working to stop shipments of weapons of mass destruction.

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An outraged North Korea then declared the truce ending the 1950-53 Korean War to be dead and threatened to attack the South.

Gates has not elaborated on how the United States might respond to North Korea, but he earlier said no additional troops will be sent to the peninsula, where 28,000 U.S. soldiers are stationed, and has stressed diplomacy in his remarks.

South Korean and U.S. troops, however, have been on heightened alert over the possibility Pyongyang may provoke an incident along the heavily armed border.

U.S. Deputy Secretary of State Jim Steinberg will lead a U.S. delegation to Asia this week to consult regional players on how to respond to North Korea’s latest nuclear test.

Stephen Bosworth, the U.S. special envoy on North Korea, was expected to accompany Steinberg on the visit to Japan, China, Russia and South Korea.

The delegation also includes Stuart Levy, the Treasury under-secretary for terrorism and financial intelligence, and Admiral James Winnefeld of the Joint Chiefs of Staff.

“It is an effort to go to each of the capitals to have a good working level discussion, to see what people are thinking and where we’re heading, what kind of ideas can be offered. And we’ll come with ideas of our own,” Morrell said.

The delegation will not visit North Korea, which has been condemned internationally since conducting the nuclear test, its second in two and a half years.

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Gates said on Saturday the United States would not accept a nuclear-armed North Korea. The Obama administration would also hold North Korea “fully accountable” if it transferred any nuclear material outside its borders, he said.

LONG-RANGE MISSILE

North Korea has warned of an intercontinental ballistic missile test in anger over U.N. Security Council punishment for what Pyongyang said was a satellite launch on April 5.

South Korean news reports at the weekend said the North was preparing to move an inter-continental ballistic missile toward a testing site on its east coast, an indication such a test might happen soon. North Korea has conducted two such tests before.

In New York, the United States and Japan have circulated a draft U.N. Security Council resolution, condemning the nuclear test and demanding strict enforcement of sanctions imposed after the North’s first atomic test in October 2006.

Western diplomats said permanent Security Council members Russia and China have agreed in principle that North Korea should be sanctioned, but it was not clear what kind of penalties they would support. Both are generally reluctant to approve sanctions.

British Minister for International Defense and Security Ann Taylor told Reuters on Sunday she remained hopeful the resolution would include tougher financial sanctions.

“There is a genuine world concern, and hopefully a consensus will come from that,” she said. “It is that unity of action that I think is important here. Because if we only can get the unity of action, the regime in North Korea will understand the strength of feeling and will begin to take notice.”

Gates also met on Saturday with China’s representative at the Asian Security Conference, Ma Xiaotian, deputy chief of staff of the People’s Liberation Army. Beijing has been reluctant to get tough with the North, up until the latest nuclear test.