Marines arrive at a Royal Australian Air Force base in Darwin, Australia, for a rotation Down Under, April 12, 2019.

The Marine Corps is boosting its presence in Australia’s Northern Territory with an extra battalion headed Down Under this summer.

The Hawaii-based 3rd Battalion, 3rd Marine Regiment will join Marine Rotational Force — Darwin in July, Marine spokesman 1st Lt. Colin Kennard said in a phone interview Thursday.

Once the 800-strong unit shows up, there will be 2,500 Marines in Australia — a target set by former President Barack Obama when he announced the creation of the rotational force during a visit to Darwin in November 2011.

The additional Marines will participate in previously scheduled activities, including Exercise Koolendong, Kennard said in an email.

“This increase … is a tangible demonstration of the United States’ sustained commitment to the U.S.-Australia alliance and to the open and free Indo-Pacific region,” he said. “It will improve security cooperation activities, disaster relief response capabilities, and the ability to respond to various crises throughout the region.”

There has been a slow build-up of the force, which rotates into Darwin for six months each summer, since an initial contingent of 250 Marines hit the beach there in 2012.

The first Marines in this summer’s rotation, which started arriving last week, include another infantry battalion — 1st Battalion, 1st Marine Regiment — an artillery battery from 3rd Battalion, 11th Marine Regiment, Combat Logistics Battalion 1 and a platoon from 1st Combat Engineer Battalion, from various bases in California, Kennard said.

The ground troops are supported by 10 MV-22 Osprey tiltrotors, four AH-1Z Vipers and three UH-1Y Venom helicopters, he said.

The rotational force commanding officer, Col. Russ Boyce, told the Australian Broadcasting Corp. that the Marines would be capable of responding if a conflict arose nearby during the rotation.

“The units that have deployed here … have trained and achieved a level of proficiency before they are able to even deploy, so certainly that’s part of the calculus,” he said.

However, Boyce added, in coming years the focus for the deployment would be on improving capabilities rather than more boots on the ground, according to the ABC.

Australian Prime Minister Scott Morrison spoke to U.S. and Australian troops at Robertson Barracks on Wednesday, Kennard said.

Morrison told troops the story of Australian stretcher-bearer Leslie “Bull” Allen, who was awarded the U.S. Silver Star medal after rescuing 12 wounded American soldiers in Papua New Guinea at the Battle of Mount Tambu in 1943, according to The Australian newspaper.

Allen’s heroism underscored the “camaraderie, kinship and spirit” between U.S. and Australian forces, the prime minister said, according to the newspaper.

robson.seth@stripes.com

Twitter: @SethRobson1