Defense Secretary Lloyd Austin is sending several thousand more U.S. troops and aircraft to the Middle East, as Israel continues to increase its attacks against Hezbollah.

Austin ordered aircraft units and their associated personnel set to leave the Middle East region to remain in the area and those set to replace them will instead join alongside them, amounting to a “few thousand” troops from multiple aircraft squadrons, Tom Crosson, a Pentagon spokesman, confirmed. The announcement followed Israeli strikes and operations in Lebanon in recent days as well as the assassination of Hezbollah leader Hassan Nasrallah on Friday.

“The secretary also increased the readiness of additional U.S. forces to deploy, elevating our preparedness to respond to various contingencies,” Pentagon spokesperson Sabrina Singh told reporters Monday. “And [the Defense Department] maintains robust and integrated air-defense capabilities across the Middle East, ensuring the protection of U.S. forces operating in the region.”

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Singh did not tell reporters specific numbers, but stated the new and existing assets in the region would include F-16, F-15E, A-10, F-22 fighter aircraft and their associated personnel.

The increase in U.S. forces comes after Israel launched strikes in Lebanon that killed Nasrallah and other key leadership in Hezbollah. On Monday, multiple news outlets reported that Israel was preparing for a potential ground incursion into Lebanon, again ratcheting up tensions in the region and threatening a wider war after a year of brutal Israeli offensives against Hamas in Gaza following that group’s terrorist attack on Israelis in October.

In addition to adding more fighter jet squadrons to the mix, Austin also ordered the USS Abraham Lincoln aircraft carrier strike group and the USS Wasp Amphibious Ready Group, which includes a Marine expeditionary unit, to remain in the region, Maj. Gen. Pat Ryder, the Pentagon’s top spokesman, said in a statement Sunday.

Military.com reported last month that the USS Abraham Lincoln strike group and the USS Wasp Amphibious Ready Group — which contains the 24th Marine Expeditionary Unit as well as the USS Oak Hill and the USS New York — would be moving into the Middle East amid the rising tensions.

Ryder said in his statement that Austin has underscored that any harm Iran does to U.S. troops in the region would be met with a swift response.

“Secretary Austin made clear that should Iran, its partners, or its proxies use this moment to target American personnel or interests in the region, the United States will take every necessary measure to defend our people,” Ryder said in the statement. “The United States retains the capability to deploy forces on short notice.”

Austin spoke twice with Israeli Minister of Defense Yoav Gallant on Friday following the violence in Lebanon where the defense secretary “expressed full support for Israel’s right to defend itself and its people against Iranian-backed terrorist groups” and “stressed that the United States is determined to prevent Iran and Iranian-backed partners and proxies from exploiting the situation or expanding the conflict,” the Pentagon said in a statement Saturday.

President Joe Biden called Nasrallah’s death “a measure of justice for his many victims, including thousands of Americans, Israelis and Lebanese civilians,” in a statement on Saturday, and he decried the former Hezbollah leader’s decision to work with Hamas to create a “Northern front” against Israel following the Oct. 7, 2023, attacks along the Gaza-Israel border.

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