Warships from four of the most powerful navies in the Indo-Pacific are together sailing to Guam from Hawaii as a combined fleet in a bold message of solidarity directed against China.

En route to Guam on this five-day mission are nine warships of the U.S. Navy, the Royal Australian Navy, the Japan Maritime Self-Defense Force and the Republic of Korea Navy.

The fleet set sail from Hawaii following the successful staging of the two week-long Exercise Rim of the Pacific off the coast of Hawaii. RIMPAC, which ended Aug. 31, drew 20 warships carrying more than 5,300 personnel from 10 navies. China again wasn't invited to take part in the biannual war games.

The combined fleet raised anchor Wednesday. The voyage intends to "improve collective readiness and response to any situation," said a statement from the fleet. The four navies will train and work together throughout the trip.

The U.S. Navy warships on this voyage are the USS Barry (DDG-52), an Arleigh Burke-class guided missile destroyer, the fleet oiler USNS John Ericsson and an unnamed U.S. fast-attack submarine.

The Australian warships are the frigates HMAS Stuart and HMAS Arunta. Japanese vessels are the helicopter carrier JDS Ise and the destroyer JDS Ashigara. Korea has included the Chungmugong Yi Sun-sin  and Seoae Yu Seong-ryong.

"This exercise provides opportunities that can enhance a steadfast and flexible coordination system," said Capt. Kim Sung Hwan, commodore of the Korean squadron. "It will also serve as an opportunity to strengthen joint response capabilities for various security situations by building up the friendship and coordination system between participating nations."

U.S. Navy Commander Christopher Gahl, commander of the USS Barry, said the fleet's voyage to Guam "is a testament to each navy's professionalism and commitment to international maritime norms and regional stability."

"Every opportunity to train and sail alongside our allied naval partners from Australia, Japan and the Republic of Korea is rewarding and mutually beneficial."

China wasn't invited by the Trump administration to join RIMPAC 2020. The Americans accuse China of militarizing the South China Sea and building artificial islands in these international waters. Warships of the People's Liberation Army Navy joined both RIMPAC 2014 and 2016 at the invitation of the Obama administration.

China state-controlled news media assailed the Trump administration for not inviting China. The Global Times, a tabloid owned by the Communist Party of China, blasted Washington for assembling the show of force and allegedly forcing allied navies into participating.