N. Korea watched for possible nuke test

SEOUL, Aug. 20 (UPI) -- South Korea has stepped up the monitoring of North Korea following a report Pyongyang may test a nuclear bomb, a military official said Sunday.

"The Defense Ministry is on a 24-hour watch to monitor the North's possible nuclear test," a ministry spokesman told The Korea Times.

The heightened alert followed an ABC News report quoting a senior U.S. military official as saying a U.S. intelligence agency had detected suspicious vehicle activity at a suspected North Korean test site.

The suspected site was an underground facility in northeastern North Korea, ABC News said.

South Korea and the United States have monitored the North's nuclear program since the 1980s, but it is unusual for Seoul to maintain the current around-the-clock vigilance, a defense official told the newspaper.

Seoul officially denied any connection between the heightened surveillance and the ABC News report.