While America’s attention was firmly fixed on Iran, China had a large fishing fleet operating illegally in Indonesia’s exclusive economic zone protected by China’s coast guard, said Rear Adm. Ken Whitesell, deputy commander of U.S. Pacific Fleet.

Indonesia deployed fighter jets and warships to “drive out the foreign vessels,” News Corp Australia reported.

It’s part of the “gray zone” tactics that fall short of the threshold of conflict “that’s very difficult to operate in, that China is trying to take advantage of,” Whitesell said Thursday at the annual Chamber of Commerce Hawaii military partnership conference.

The Middle East remains in the headlines, but the Indo-Pacific is the Defense Department’s priority theater with the rise of China as a revisionist power and resurgence of an interfering Russia.

Top-ranking military commanders raised concern Thursday over a China that has claimed much of the South China Sea, extended its reach to the World War II steppingstone islands of Oceania and established an economic grip as far as Pana­ma, home of the well-known and vitally important shipping canal.

“China is operating across this region” to include Pacific island nations “in a real disturbing way, and they are creating potential vulnerabilities with our friends and teammates out there,” Maj. Gen. John “Pete” Johnson, deputy commander of U.S. Army Pacific, told about 150 conference attendees at the state Capitol.

Some of those nations have compacts of association with the United States that America needs to “square up to,” he said.

“And the way that we square up to that is by being there (in those islands) and by representing what it means to be free and open,” he said. Indeed, the title of the panel discussion was “Free and Open Pacific.”

A whole-of-government approach is taken to counter what the United States views as a malicious overreach by China intended to displace American values, and the Hawaii military commanders laid out steps underway to improve security in the face of not only Chinese, but also Russian and North Korean challenges.

Johnson said one of the key ways the Army generates goodwill and promotes a free and open Indo-Pacific is through its Pacific Pathways deployments that send soldiers out to train in and with partner nations for five months at a time.

This year Pacific Pathways will include a first-ever Oceania deployment to locations including Timor-Leste, Papua New Guinea, Vanuatu, Tonga, Fiji, Palau and Yap, Johnson said.

“And it’s going to allow us to generate a degree of presence that we are going to find really, really valuable,” he said.

Lt. Gen. Michael Minihan, deputy commander of U.S. Indo-Pacific Command, said Oceania “is the high ground” of the region. “It was in the ’40s (during World War II) and it is now.”

“If you own, or don’t own, Oceania, it will determine whether you can project power into the South China Sea,” he said.

Whitesell said the Navy already has 60% of its forces in the Pacific, and it’s bringing the latest technology to the region, such as F-35 Lightning II stealth jets.

The Marine Corps already has short-takeoff F-35s in Japan. The aircraft carrier USS Theodore Roosevelt will soon deploy from the West Coast with the carrier version of the jets, he said.

Whitesell said the Navy has two littoral combat ships in Singapore, is negotiating for a third and is also seeking to have a cruiser/destroyer hub there.

Air Force Maj. Gen. Brian Killough, deputy commander of Pacific Air Forces, said allies and partners are also leading the way with F-35s in South Korea, Japan and Australia.

The Air Force will receive its first F-35s at Eielson Air Force Base in Alaska in about three months, he said.

“By 2025 there will be over 240 F-35s in this theater,” with 70% of those owned by allies, according to Killough.

During Rim of the Pacific exercises this summer in Hawaii, meanwhile, Sea Hunter, a 132-foot robot warship that became the first ship to successfully navigate autonomously from San Diego to Pearl Harbor and back to San Diego, is making a return appearance.

“That’s going to be practiced here at RIMPAC in June and July as we start to rely (on) and bring into our quiver” unmanned surface and underwater vessels in the Pacific, Whitesell said.