South Korea ? North Korea fired a barrage of short-range missiles off its east coast in a possible prelude to the launch of a long-range missile toward Hawaii over the U.S. Independence Day holiday.

Firing a ballistic missile on the July Fourth celebration would be a challenge to Washington, which has been rallying international support for enforcement of U.N. sanctions imposed against Pyongyang following a May 25 nuclear test. North Korea is banned from testing ballistic missiles under U.N. resolutions.

Japan’s Chief Cabinet Secretary Takeo Kawamura said Thursday that a long-range missile launch this weekend was possible. “We cannot rule out the possibility,” he said, citing Pyongyang’s past behavior.

In 2006, North Korea launched its most advanced Taepodong 2 missile while the U.S. celebrated Independence Day, though the rocket fizzled shortly after takeoff and fell into the ocean.

Pentagon spokesman Bryan Whitman said the United States remains concerned about North Korea’s missile and nuclear programs but called North Korea’s launches Thursday of short-range missiles “not unexpected.”

Several U.S. Defense Department officials said there is nothing to indicate that North Korea is ready to launch a long-range ballistic missile and there appears to be no immediate threat to the United States.