North Korea has started moving a long-range missile towards a launch pad in possible preparation for another missile test, according to US officials.

One told the Financial Times that Pyongyang may be gearing up for “additional activity” just days after it defied the world by conducting a nuclear test.

Last month North Korea fired a long-range Taepodong-2 missile over Japan. This followed a previous test in 2006.

Amid mounting concerns about the situation, James Steinberg, US deputy secretary of state, led a US delegation to Tokyo on Sunday for talks on North Korea. He was expected to continue to Seoul, Beijing and Moscow.

US officials attending the Shangri-La defence forum in Singapore at the weekend said Washington had new ideas for dealing with North Korea, but declined to provide details. The US is also pushing the United Nations Security Council to impose tough new sanctions on Pyongyang.

South Korea’s Yonhap news agency cited an intelligence official saying North Korea was transporting a long-range missile, similar to the Taepodong-2 fired last month, on a train.

While the US official confirmed the missile movement, he cautioned that Pyongyang might be engaging in deception. In the past, the regime has shifted equipment – knowing that US spy satellites would detect the movement – to generate a crisis.

Robert Gates, US defence secretary, told the defence forum that Barack Obama’s administration would continue to pursue the six-party talks aimed at de-nuclearising the Korean peninsula.

But he hinted that Washington would adopt a harder-nosed approach. In a reference to North Korea’s tendency to ratchet up tensions to extract concessions, he said the US was “tired of buying the same horse twice”.

Mr Gates also held trilateral defence talks with his Japanese and South Korean counterparts. US defence officials said he suggested the need to bolster regional military defences if the six-party talks failed. Japan and South Korea are particularly concerned about missile launches from North Korea.

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