WASHINGTON: The US Defense Department is 'looking into reports of a possible seismic event near North Korea's nuclear facilities,' a US official said on Tuesday. South Korea's meteorological agency said earlier that North Korea is 'likely' to have conducted a nuclear test that caused an earthquake near a known testing site in the isolated country. 'We are looking into the reports of a possible seismic event near North Korean nuclear facilities,' said a US official, who spoke on condition of anonymity.