Thomas Maresca

Special for USA TODAY

Amid rising tensions with North Korea, an aircraft carrier strike group led by the USS Carl Vinson was heading toward the Korean Peninsula.

The aircraft carrier and its accompanying ships had been scheduled to leave from Singapore for port visits to Australia on Saturday, but Adm. Harry Harris, head of U.S. Pacific Command, ordered the strike group to head north toward Korean waters instead.

“U.S. Pacific Command ordered the Carl Vinson Strike Group north as a prudent measure to maintain readiness and presence in the Western Pacific,” Cmdr. Dave Benham said in a statement.

“The number one threat in the region continues to be North Korea, due to its reckless, irresponsible and destabilizing program of missile tests and pursuit of a nuclear weapons capability," he added.

North Korea's provocative behavior in recent months has raised tension levels in the region and is emerging as one of the key foreign policy and defense challenges for the new Trump administration.

The secretive communist state test-fired a ballistic missile on April 5 into the Sea of Japan, ahead of Thursday’s meeting between President Trump and Chinese President Xi Jinping. The missile appeared to malfunction during flight before crashing into the sea and flew only about 40 miles, according to U.S. defense officials.

The launch is the latest in a recent series of missile tests by North Korea, which maintains a nuclear weapons program. On March 6, North Korea launched four ballistic missiles, which traveled over 600 miles before descending into the Sea of Japan. Another attempted test on March 22 failed after the missile exploded within seconds of launching.

The China-U.S. presidential summit, held at Mar-a-Lago in Florida on Thursday and Friday, failed to deliver any concrete agreement on how to rein in North Korea's nuclear and ballistic missile programs between the two nations. China has long been North Korea's primary ally, supporting the hermit state with food, energy and most of its economic trade.

In comments to reporters, Secretary of State Rex Tillerson said the countries had agreed to increase cooperation in pushing North Korea to abandon its weapons programs, but made it clear that the U.S. was willing to go it alone in tackling the problem.

“President Trump indicated to President Xi ... that we would be happy to work with them, but we understand it creates unique problems for them and challenges and that we would, and are, prepared to chart our own course if this is something China is just unable to coordinate with us," he said.

Some observers speculated that Thursday’s missile strike against Syria was also intended to send a warning message to Pyongyang. Tillerson underplayed any connection, but he said strikes against Syria signaled the president’s readiness to take action.

"I think it does demonstrate that President Trump is willing to act when governments and actors cross the line, and cross the line on violating commitments they have made and cross the line in the most heinous of ways," he said.

North Korea condemned the airstrikes, saying they proved that the North's nuclear weapons were necessary for its own defense, according to a report Sunday on the state-run Korean Central News Agency. "We will bolster up in every way our capability for self-defense to cope with the U.S. ever more reckless moves for a war and defend ourselves with our own force," the Associated Press quoted from the report.

Ships and units from the Carl Vinson Strike Group departed from San Diego on Jan. 5 for a regularly scheduled deployment to the western Pacific. The aircraft carrier sailed through the contentious South China Sea in February on freedom of navigation operations that drew condemnation from China. It also conducted exercises with Japanese warships and South Korean forces in March.