Pyongyang remained defiant on Sunday, with the ruling parties newspaper publishing a commentary likening the US aircraft carrier to a "gross animal" and threatening to strike it.

"Our revolutionary forces are combat-ready to sink a US nuclear powered aircraft carrier with a single strike," the "Rodong Sinmun" newspaper said. 

A spokesperson for the USS Carl Vinson posted on its Facebook page on Sunday that the strategic maneuvers and communication drills would last several days.

"We always look forward to operating with our Japanese partners," the carrier strike group's commander Rear Admiral Jim Kilby, was quoted as saying. "The relationship between the JMSDF [Japanese self defense force] and the United States is better than ever and it's in part thanks to these bilateral exercises."

US Vice President Mike Pence said during a visit to Australia on his tour of Asia on Saturday that the Carl Vinson would be in the Sea of Japan within days. The aircraft carrier and accompanying warships are heading toward waters off the Korean Peninsula in a show of force amid elevated tensions. On April 8, the US Navy said it had directed the naval strike group to divert to North Korea from Singapore, but it has since emerged that the group sailed south first to conduct drills with the Australian navy.

Threats and counter-threats

North Korea has pushed forward with its nuclear and missile programs under leader Kim Jong Un, despite international condemnation. China, which opposes Pyongyang's weapons build-up and belligerence, but which remains the reclusive state's only major ally, has called for calm. The US has urged China to do more to rein in North Korea but did not rule out acting unilaterally.

Read: Guns, gold and gas. What UN sanctions target North Korea?

Australian Foreign Minister Julie Bishop said North Korea "should invest in the welfare of its long-suffering citizens, rather than weapons of mass destruction," after Pyongyang threatened Australia by saying Canberra's continued support for the US would be a "suicidal act."

Another anniversary, another test?

There are growing concerns that Pyongyang might conduct another nuclear test or fire more ballistic missiles to coincide with when North Korea marks the 85th anniversary of its army on Tuesday. Its latest ballistic missile launch attempt was on April 16, shortly after the country marked the 105th birthday of its late founding leader, Kim Il Sung. The launch failed.

The US, South Korea and Japan regularly conduct military and training exercises together. The most recent of the bilateral exercises between the Carl Vinson strike group and Japanese forces took place in March.

se/rc (AP, AFP, dpa, Reuters)