WASHINGTON >> The U.S. has increased its military presence in the Middle East by several thousand troops, sending an array of fighter jets and other aircraft to bolster the protection of U.S. forces and allies.

The decision brings the total number of American troops in the region to as many as 43,000, including more than a dozen warships.

Israel’s latest surge in attacks in Lebanon, including strikes that killed Iran-backed Hezbollah leader Hassan Nasrallahand several of his top commanders, and Iran firing at least 180 ballistic missiles at Israel are significant escalations that have fueled fears of all-out war in the Middle East.

Defense Secretary Lloyd Austin has increased the readiness levels of additional U.S. forces so they are prepared to deploy for any contingency, said Air Force Maj. Gen. Pat Ryder, Pentagon spokesman.

Risk to American forces has increased. U.S. military leaders are now in “almost daily” discussions with their Israeli counterparts on what Israel’s response might be to Iran’s missile attack. And threats continue throughout Iraq, Syria and in the Red Sea, where Iranian-backed militias threaten U.S. bases and commercial ships.

“We have forces throughout the region,” Pentagon spokeswoman Sabrina Singh told reporters. “Any type of action has potential impacts for our forces.”

Normally, about 34,000 U.S. forces are deployed to U.S. Central Command, which covers the entire Middle East. That number grew in the early months of the Israel-Hamas war to about 40,000 as additional ships and aircraft were sent in.

It spiked to nearly 50,000 when Austin ordered two aircraft carriers and their accompanying warships to stay in the region as tensions roiled between Israel and Lebanon.

The Pentagon recently said it was sending a small number of additional troops to the Middle East.

The U.S. has one aircraft carrier in the region, the USS Abraham Lincoln, which had been slated to leave around mid-October. Austin has extended its deployment for about another month, according to one of the officials.

A second carrier, the USS Harry S. Truman, along with two destroyers and a cruiser, are in the Atlantic Ocean heading east. They will be in the European region in a few days and then travel into the Mediterranean Sea.

American military commanders have long argued that the presence of a formidable aircraft carrier — with its array of fighter jets and surveillance aircraft and sophisticated missiles — is a strong deterrent against Iran.

The Air Force sent in an additional squadron of advanced F-22 fighter jets in August, bringing the total number of land-based fighter squadrons in the Middle East to four.

That force also includes a squadron of A-10 Thunderbolt II ground attack aircraft, F-15E Strike Eagles and F-16 fighter jets. The Air Force is not identifying what countries the planes are operating from.

The U.S. was now sending in more aircraft, Pentagon spokeswoman Sabrina Singh said. The additional personnel includes squadrons of F-15E, F-16 and F-22 fighter jets and A-10 attack aircraft, and the personnel needed to support them. The jets were supposed to rotate in and replace the squadrons already there. Instead, both the existing and new squadrons will remain in place to double the airpower on hand.

The squadrons would not be used in any evacuation of American citizens but would be used to defend U.S. forces and Israel if necessary, Singh said.

The addition of the F-22 fighter jets gives U.S. forces a hard-to-detect aircraft that has a sophisticated suite of sensors to suppress enemy air defenses and carry out electronic attacks. The F-22 also can act as a “quarterback,” organizing other warplanes in an operation.

But the U.S. also showed in February that it doesn’t have to have planes based in the Middle East to attack targets. In February, a pair of B-1 bombers took off from Dyess Air Force Base in Texas, flew more than 30 hours and struck 85 Islamic Revolutionary Guards Corps Quds Force targets.