The Trump administration is finalizing a $4.5 billion sale of the Terminal High-Altitude Area Defense (THAAD) system to the United Arab Emirates. Lockheed Martin will serve as the prime contractor for the transaction.

The Defense Department plans to publish a memo detailing the proposed sale on Tuesday morning. This deal coincides with a U.S. naval blockade of the Strait of Hormuz and heightened regional tensions with Iran.

The THAAD system intercepts ballistic missiles fired against U.S. assets and allies. This agreement marks the latest in a series of major arms deals for Lockheed Martin, the world’s largest military contractor.