The US Navy is on its fourth aircraft carrier as its warships react to fighting in the Middle East

• The US on Saturday dispatched an aircraft carrier, USS Abraham Lincoln, to the Middle East.
• It's the fourth US carrier sent to respond to ongoing crises in the Middle East since October.
• The change has come as the region braces for a potential attack on Israel by Iran and its proxies.

The US Navy is sending another aircraft carrier to the Middle East. It's the fourth sent to respond to ongoing crises in the tumultuous region in the past 10 months. With this move, more than a third of the carrier fleet will have been involved at one point or another.

The Pentagon on Saturday announced that the USS Abraham Lincoln Carrier Strike Group, which was recently in the Pacific, was moving into the Middle East amid a broader shake-up of the US military's force posture in the region.

The change has come as the US, its allies and partners, and the broader Middle East brace for a potential attack on Israel by Iran and its proxies. They've blamed Israel for the stunning assassination of Hamas' political chief in Tehran, Iran's capital, last week and vowed to take revenge for the killing.

It's not immediately clear when the Lincoln and the other ships in the carrier strike group will arrive in the region. When they do, the strike group will be the fourth to be deployed to the Middle East or nearby Eastern Mediterranean since Hamas staged its brutal October 7 attack in Israel, igniting a war and fueling regional tensions.

The massacre triggered a retaliatory war in Gaza and sparked conflict involving other Iranian proxy groups across the region, including the Houthis in Yemen, Hezbollah in Lebanon, and various militias in Iraq and Syria.

The US, in October, initially directed the USS Gerald R. Ford Carrier Strike Group to the Eastern Mediterranean to prevent the fighting from spiraling and signal its support for Israel.

A carrier strike group consists of a carrier, its air wing, and other warships such as destroyers and cruisers. It's a tremendous and flexible show of force that provides lots of firepower for both offensive and defensive operations.

The US also deployed the Dwight D. Eisenhower Carrier Strike Group to the Eastern Mediterranean as regional tensions flared. It then pivoted to the Middle East to defend merchant shipping lanes in the Red Sea and Gulf of Aden from Houthi attacks.

The Ford returned home in January. And after months of battling the Houthis in what has been described as the Navy's most intense combat operations since World War II, the Eisenhower finally left the Middle East in June, returning to the US.

The carrier was replaced last month by the USS Theodore Roosevelt Carrier Strike Group, which was previously operating in the Indo-Pacific region, where the US doesn't currently have a forward-deployed carrier presence.

Now, the Lincoln carrier strike group is set to replace the Roosevelt, which was operating in the Persian Gulf as of last week, according to the USNI News Fleet and Marine Tracker . It's unclear where the Roosevelt is headed next.

"The United States' global defense is dynamic and the Department of Defense retains the capability to deploy on short notice to meet evolving national security threats," a Pentagon spokesperson said on Saturday.

The Pentagon said the US was dispatching additional warships capable of intercepting ballistic missiles to the US Central Command and US European Command areas of responsibility as tensions soar between Israel and Iran and its proxies.

US warships helped down Iranian ballistic missiles during Tehran's massive attack on Israel in April. It's unclear what a retaliatory Iranian attack could involve, but analysts say Iran and its proxies could modify that strike package as they continue to signal their intent to retaliate against Israel in the coming days.