It could cost about $60 million to replace the cruise missiles that the U.S. military rained on Syrian targets Thursday night.

Each Tomahawk missile, made by Raytheon Co. US:RTN, likely cost $1 million, according to experts.

The U.S. used 59 of them on a Syrian air base in response to the Syrian government’s chemical-weapons attack that killed scores of civilians earlier this week.

Raytheon referred questions around costs to the U.S. Navy’s unmanned aviation and strike weapons program, which did not immediately return a request for comment.

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The missiles used on Thursday likely cost the U.S. military around $1 million, but the latest versions of the missile that would replace those could be more costly, depending on size of the order and other factors, said Loren Thompson, a consultant and chief operating officer of nonprofit Lexington Institute.

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Demand for Tomahawks never seems to go down, said Tom Karako, a director at the Center for Strategic and International Studies. Karako estimated a replacement cost for each Tomahawk of around $1 million.

The Navy’s 2017 budget has the future missiles at a unit cost of $1.5 million, higher than previous years, but that is probably because the Navy is winding down the program and does not plan, at least for now, on buying more Tomahawks after this year, said Todd Harrison, also a director with CSIS.

Tomahawks can be launched from a ship or a submarine. Yesterday’s Tomahawk missiles were launched from two U.S. Navy destroyers in the Mediterranean Sea, according to reports.

Tomahawks have been part of the U.S. military’s arsenal for three decades, and were first used during the 1991 Gulf War. Newer iterations of the missile were last used in October to strike targets in Yemen after attacks on U.S. Navy ships.

The value of the Tomahawk comes from their long range, their precision, and the fact that they don’t require putting a pilot in hostile airspace, said the Lexington Institute’s Thompson.

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According to Raytheon’s website, the cruise missile has been employed in combat more than 2,000 times since it was introduced.

Tomahawks can fly about 1,000 miles at subsonic speeds (around 550 miles an hour), and its latest version, the Tomahawk Block IV, can be pre-programmed as well as redirected to a new target in real time and during its flight. The Tomahawk is also the weapon of choice of the British military.