In a rare announcement, the US military said a guided missile submarine has arrived in the Middle East, a message of deterrence clearly directed at regional adversaries as the Biden administration tries to avoid a broader conflict amid the Israel-Hamas war. US Central Command said on social media Sunday that an Ohio-class submarine was entering its area of responsibility. A picture posted with the announcement appeared to show the sub in the Suez Canal northeast of Cairo. The social media post did not name the sub, but the US Navy has four Ohio-class guided missile submarines, or SSGNs, which are former ballistic missile subs converted to fire Tomahawk cruise missiles rather than nuclear-tipped ballistic missiles. Each SSGN can carry 154 Tomahawk cruise missiles, 50% more than US guided-missile destroyers pack and almost four times what the US Navy's newest attack subs are armed with. Each Tomahawk can carry up to a 1,000-pound high-explosive warhead. "SSGNs can deliver a lot of firepower very rapidly," said Carl Schuster, a former director of operations at the US Pacific Command's Joint Intelligence Center told CNN in 2021. "One-hundred and fifty-four Tomahawks accurately deliver a lot of punch. No opponent of the US can ignore the threat." The magnitude of that firepower was shown in March 2011, when the guided missile sub USS Florida fired almost 100 Tomahawks against targets in Libya during Operation Odyssey Dawn. The attack marked the first time the SSGNs were used in combat. The military rarely announces the movements or operations of its fleet of ballistic and guided missile subs. Instead, the nuclear-powered vessels operate in near-complete secrecy. The announcement is a clear message of deterrence directed at Iran and its proxies in the region. The sub joins a number of other US Navy assets already in area, including two carrier strike groups and an amphibious ready group. In April, the Navy announced that the USS Florida, one of the two East Coast-based SSGNs, was operating in the Middle East. In June, the Navy publicized the visit of one of its two West Coast-based SSGN's, USS Michigan, to South Korea as a show of US commitment to its Indo-Pacific allies. The announcement of a guided missile sub in the region comes as US Secretary of State Antony Blinken has been holding a series of meetings with US partners in the Middle East. In a whirlwind trip, Blinken has visited Turkey, Iraq, Israel, the West Bank, Jordan and Cyprus. On Sunday, Defense Secretary Lloyd Austin spoke with his Israeli counterpart, Minister of Defense Yoav Gallant. In addition to emphasizing the need to protect civilians and provide humanitarian assistance to Gaza, Austin said the US was committed to deterring "any state or non-state actor seeking to escalate this conflict," a clear reference to Iran and Hezbollah, the Iran-backed armed group. There have been frequent low-level attacks on US forces in Iraq and Syria by Iranian-backed groups, but the US has been aiming to make it clear that wider attacks would provoke a major response. Austin said this month that the additional forces in the area were meant to "bolster regional deterrence efforts, increase force protection for US forces in the region, and assist in the defense of Israel." "We will do everything and take all necessary measures to protect US forces and our interests overseas," Brig. Gen. Pat Ryder, the Pentagon press secretary, said October 23. "Again, no one wants to see a widening conflict, and that is our primary goal, but we will also never hesitate to protect our forces." — BBC