SEOUL, July 2 (AP): North Korea is highly likely to test-fire a barrage of missiles in coming days, a news report said Thursday, a move that would aggravate the already-high tensions following Pyongyang's nuclear test and UN sanctions.

The North is expected to launch short- or medium-range missiles, including banned ballistic rockets, from two sites on its east coast in early July, the South Korean newspaper JoongAng Ilbo reported, citing an unidentified intelligence source.

Last month, Pyongyang designated a no-sail zone off its east coast for military drills through July 10. Media reports have said the missile launches could come around July 4, the US Independence Day. The North tested a long-range missile on that day in 2006.

New missiles launches would seriously exacerbate the tensions running high since Pyongyang's May 25 nuclear test and a series of missile firings. The UN Security Council adopted a tough sanctions resolution last month to punish the communist regime.

Versions of short-range Scud or medium-range Rodong missiles are expected to be fired from one site in Anbyon, the JoongAng said. The Scud B missile has a range of 340 kilometres and the Rodong 1 has a range of more than 1,000 kilometres, it said.

But the North could cut Rodong's range to some 400 kilometres for the upcoming test-firing, the paper cited the source as saying without elaborating. Both Scud and Rodong are ballistic missiles that the North is banned from testing under UN resolutions.

The North is expected to launch short-range ground-to-ship missiles from the other site, the mass-market paper said.

But Seoul's Yonhap news agency cited an unidentified military official saying later that there are no signs yet that missile launches are imminent, though added that short-range missiles can be fired at any time.

South Korea's Defence Ministry declined to confirm the reports, saying it cannot discuss intelligence matters.

The North also threatened in April to test-fire an intercontinental ballistic missile. Last month, a Japanese newspaper reported that the North could test-fire a long-range missile toward Hawaii as early as around July 4. The US has beefed up defenses around Hawaii.

But Seoul's YTN television news network said Thursday there are no signs of an imminent long-range missile launch.

The reported missile moves came after a North Korean ship - suspected of possibly carrying illicit weapons - changed course and was heading back the way it came after remaining under US surveillance for more than a week.

The North Korean ship is the first vessel monitored under the new UN sanctions that seek to clamp down on Pyongyang's trading of banned arms and weapons-related material by requiring UN member states to request inspections of ships suspected of carrying prohibited cargo.

The North has said it would consider interception of its ships a declaration of war. On Wednesday, North Korea's main Rodong Sinmun newspaper renewed the warning.

"Touching our ships constitutes a grave military provocation against our country," the paper said in a commentary carried by the official Korean Central News Agency. "These acts will be followed immediately by self-defensive military countermeasures."