WASHINGTON -- US satellite photos have revealed vehicle activity at a site in North Korea suggesting the regime may be preparing to launch a long-range ballistic missile, two US defense officials said on Friday.
The vehicle movements resembled work done before North Korea fired a long-range rocket last month, the officials, speaking on condition of anonymity, told AFP.
The officials offered no other details but said the United States was closely monitoring North Korea's missile sites and other sensitive facilities amid rising tensions on the peninsula.
The officials also said there was no steam or other tell-tale sign coming from the Yongbyon plutonium reprocessing plant but it remained unclear if the regime had restarted work at the plant.
Tensions have been running high since Kim Jong-Il's regime tested an atomic bomb for the second time and renounced the armistice that ended the Korean War in 1953.
North Korea on Friday fired a short-range missile, its sixth since Monday, and threatened to take new measures to defend itself if world powers impose sanctions over its nuclear test.
In April, the launch of the long-range rocket was portrayed by Pyongyang as a peaceful move to test a communications satellite. But the United States and its allies said the launch was meant to be a test of a long-range missile.
Japan said the rocket flew over its territory while the boosters landed safely in the waters off its coasts, and that it had not moved to intercept the rocket -- something North Korea had warned would be seen as an act of war.
Pyongyang's Taepodong-2 missile could theoretically reach the US states of Alaska or Hawaii at maximum range, though experts say North Korea has likely not managed to configure a warhead for it yet.
US Defense Secretary Robert Gates meanwhile accused the North of "very provocative, aggressive" actions but played down the possibility of military action.
Gates said he was unaware of any unusual troop movements in the North, which has around 1.1 million soldiers, compared with 680,000 South Korean and 28,500 US troops south of the border.
"I don't think there is a need for us to reinforce our military presence in the South. Should the North Koreans do something extremely provocative militarily, then we have the forces to deal with it," he said en route to a regional security meeting in Singapore.
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