(CNN) The first phase of Saudi Arabia's long awaited purchase of an advanced US missile defense system has been finalized with the formal awarding of a contract on Monday.
Lockheed Martin was awarded a contract for Phase I "long lead items" of the Terminal High Altitude Area Defense (THAAD) missile defense system, to include early engineering development, test equipment, key personnel and initial training development, according to a statement from the Pentagon.
The Defense Department said the first phase of the contract will cost $945,900,000.
The State Department had previously estimated the cost of the entire THAAD sale to be $15 billion.
President Donald Trump included the THAAD purchase in his list of proposed $110 billion in arm sales that he touted during his 2017 meeting with King Salman bin Abdulaziz Al Saud.
The list was a memorandum of intent to fulfill nearly $110 billion in arms sales over the next 10 years. What the Pentagon announced Monday is the first installment on the THAAD sale.
However, despite the administration's touting of the agreement, the majority of the $110 billion package was not finalized at the time of it being announced and it has taken months for progress on the sale to be made.
The announcement comes at time the US-Saudi relationship is under bipartisan scrutiny in Washington.
Lawmakers on both sides aisle are angry at the administration's response to the murder of Washington Post columnist Jamal Khashoggi in the Saudi Consulate in Istanbul last year.
CNN has reported that US intelligence agencies have concluded that the killing and dismembering of the journalist was ordered by the Saudi Crown Prince Mohammed bin Salman, despite the Saudi government's denials.
The administration infuriated senators by ignoring a February deadline to provide a report on the murder, and Trump has repeatedly warned that Saudi Arabia's purchases of US weapons and its role in helping the administration confront Iran are not worth jeopardizing over the episode.
And it emerged over the weekend that a dual US-Saudi citizen is being held in Saudi Arabia. Dr. Walid Fitaihi has reportedly been beaten, tortured and jailed, a source familiar with the situation tells CNN,
In October 2017, the State Department notified Congress that it had approved the possible sale of the THAAD system to Riyadh, saying that the sale of the missile system "furthers US national security and foreign policy interests, and supports the long-term security of Saudi Arabia and the Gulf region in the face of Iranian and other regional threats."
The THAAD system "will substantially increase Saudi Arabia's capability to defend itself against the growing ballistic missile threat in the region," the statement added.
CNN previously reported that Saudi Arabia's decision to purchase the system was finalized in part thanks to the direct involvement of Jared Kushner, the President's son-in-law and senior adviser.
He shocked a high-level Saudi delegation when he personally called Lockheed Martin CEO Marillyn Hewson and asked if she would cut the price of a sophisticated missile detection system, according to a source with knowledge of the call.
Pressured to finalize a massive $100-plus billion arms deal in the two weeks leading up to Trump's trip to Saudi Arabia, Kushner hoped to maneuver a discount on Lockheed's Terminal High Altitude Area Defense (THAAD) system during the Saudis' visit to the White House on May 1 -- a request that Hewson said she would look into at the time.