Col. John DiGiambattista, right, 1st Armored Brigade Combat Team, 1st Cavalry Division commander, discusses the brigade's nine-month rotation to South Korea with Maj. Gen. Kyoung Soo Shin, South Korea's defense attache to the United States, after a colors casing ceremony on Cooper Field at Fort Hood, Texas, Jan 28, 2016. Ironhorse soldiers will participate in several joint and multinational exercises with South Korean forces, and work with Korean augmentees to the United States.

Members of the 1st “Ironhorse” Armored Brigade Combat Team, 1st Cavalry Division are arriving in South Korea amid rising tensions after North Korea tested an atomic bomb last month and launched a rocket Sunday.

The Fort Hood, Texas-based brigade is replacing its sister unit, 1st Cavalry’s 2nd “Blackjack” Armored Brigade Combat Team, which is wrapping up a nine-month rotational deployment.

The units are the first rotational brigades to deploy under a plan that has seen the 2nd Infantry Division inactivate the 1st “Iron” Brigade Combat Team, based in South Korea since 1965, and transform it into a combined U.S.-South Korea unit.

At his new Camp Hovey headquarters Monday, Ironhorse commander Col. John P. DiGiambattista said about 40 percent of his 4,000 soldiers are already in South Korea with the rest expected to arrive by month’s end.

He said the troops prepared for their mission last spring with small-unit training followed by force-on-force and gunnery exercises in October at Fort Irwin National Training Center, Calif., and cultural training back at Fort Hood.

“The North Korean missile launch reinforced the importance of our mission,” DiGiambattista said.

Ironhorse soldiers are used to deterring hostility, he said, noting the unit’s recent deployment to Latvia, Lithuania and Estonia as part of Operation Atlantic Resolve, launched in response to Russian aggression in Ukraine.

“We are excited about training with the (South Korean) army,” said DiGiambattista, who has already met with Brig. Gen. Yin Sung-hwan, the 2nd ID deputy commander, and Col. Ha Sung Woo, commander of the 16th Mechanized Infantry Brigade, 8th Infantry Division, South Korean army.

The Ironhorse brigade will be in South Korea until October, when it will be replaced by another rotational unit. It’s unclear whether that brigade will stay at Camp Casey-Hovey or go directly to new facilities at Camp Humphreys, south of Seoul, DiGiambattista said.

The brigade’s deployment coincides with a rotation of U.S. Special Operations personnel, who recently arrived on the Peninsula to train with their South Korean counterparts, a U.S. Forces Korea statement said. The rotation includes elements from the 1st Special Forces Group (Airborne) and the 75th Ranger Regiment.

The rotational deployment provides ready, flexible and agile combined special operation forces to deter regional asymmetric aggression, and maintain peace for the Korean people, USFK said.

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