WATCH: Pentagon speaks on U.S. raid in Syria, North Korea tensions

Pentagon Press Secretary Air Force Brig. Gen. Pat Ryder says the threat from IS in Syria “is not a new thing”but efforts to combat IS “still continues because the threat still exists” during a Thursday briefing at the Pentagon.

Watch Ryder’s remarks in the player above.

“Our focus is to continue to work with our partners in the region by, with, and through to eliminate that threat and hopefully prevent it from spreading further,” he said.

U.S. special operations forces conducted a raid in northeast Syria overnight, killing an Islamic State insurgent who was involved in smuggling weapons and fighters, U.S. officials said Thursday.

U.S. officials said a small number of U.S. troops were on the ground near the village of Qamishli for less than an hour to conduct the raid.

In a statement, U.S. Central Command said that the helicopter raid targeted Rakkan Wahid al Shamman, who was known to facilitate the smuggling in support of IS operations.

The statement said he was killed in the raid, and that one IS insurgent was wounded and two others were captured and detained.

According to the statement, no civilians or U.S. troops or were killed or injured in the raid.

The U.S. continues to have about 900 forces in Syria to advise and assist Syrian Democratic Forces in the fight against the Islamic State group.

Meanwhile, South Korea says North Korea flew 12 warplanes near their mutual border on Thursday, prompting South Korea to scramble 30 military planes in response.

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The highly unusual incident came hours after North Korea fired two ballistic missiles into the sea in its sixth round of missile tests in less than two weeks.

South Korea’s military says eight North Korean fighter jets and four bombers flew in formation near the border and are believed to have conducted air-to-surface firing drills.

“We consider this behavior destabilizing, unhelpful and irresponsible. And again, we call on the DPRK to cease these types of actions,” Ryder told reporters in a briefing.

Tensions have risen sharply on the Korean Peninsula as North Korea’s recent barrage of missile tests prompted South Korea, the United States and Japan to conduct joint drills in response.

U.S., South Korean and Japanese destroyers launched joint drills later Thursday off the Korean Peninsula’s east coast to horn their abilities to search, track and intercept North Korean ballistic missiles, South Korea’s Joint Chiefs of Staff said.

The U.S. destroyer is part of the strike group led by the nuclear-powered aircraft carrier USS Ronald Reagan, which returned to the waters in what South Korea’s military called an attempt to demonstrate the allies’ “firm will” to counter North’s continued provocations and threats.

“These are defensive exercises that are focused on how we would defend ourselves and how we would deter. And they are not a threat at all to the region. Unlike the provocative activities coming from North Korea regime”, Ryder said.

The strike group was in the area last week as part of previous drills between South Korea and the United States, and the allies’ other training involving Japan.

North Korea considers such U.S.-led drills near the peninsula as an invasion rehearsal and views training involving a U.S. carrier as more provocative.