Israel finalized its agreement to buy 17 more advanced F-35 stealth fighters from Lockheed Martin on Sunday, the Defense Ministry said, which will bring the air force’s fleet of the aircraft to 50.

The initial decision to purchase the 17 additional F-35 fighters was made by the security cabinet in November 2016, but it took an additional nine months to hammer out the agreement with the United States and Lockheed Martin.

Israel is currently in possession of five F-35 stealth fighters, the first of them delivered in December 2016, and the air force will continue to receive the remaining 45 in small batches over the next few years.

The initial order of 33 F-35 jets is expected to be completely delivered by 2021. The new batch of 17 airplanes is set to arrive by December 2024, the Defense Ministry said in a statement.

An F-35 fighter jet lands in the Nevatim air base in southern Israel on December 12, 2016. (Judah Ari Gross/Times of Israel)

An F-35 fighter jet lands in the Nevatim air base in southern Israel on December 12, 2016. (Judah Ari Gross/Times of Israel)

According to the air force, the state-of-the-art aircraft are expected to be declared operational by next year.

“Completing the deal to acquire 17 F-35 planes represents a significant and strategic addition of strength to the air force,” Defense Minister Avigdor Liberman said in a statement.

The defense minister also noted that this deal is further evidence of “how deep the connection and military relations are between the State of Israel and our great friend the United States.”

In its statement, the Defense Ministry would not specify the exact cost of the fighters, but it noted that for the first time, the F-35 jets will cost under NIS 358 million ($100 million) per airplane, which means the additional aircraft will likely set Israel back at least NIS 6.09 billion ($1.7 billion), not including the costs of additional maintenance and support equipment.

Lockheed Martin unveils Israel's first F-35 fighter jet in Fort Worth, Texas, on June 22, 2016. (Lockheed Martin)

Lockheed Martin unveils Israel’s first F-35 fighter jet in Fort Worth, Texas, on June 22, 2016. (Lockheed Martin)

Dovi Lavi, the head of the Defense Ministry’s delegation in Washington, praised the US Defense Department for negotiating with Lockheed Martin to bring down the price.

“This is a significant decrease in price compared to the airplanes that the State of Israel has purchased until now,” Lavi said.

The F-35 — known in Israel as the Adir, meaning “awesome” or “mighty” in Hebrew — is a fifth-generation stealth fighter jet equipped with an array of the latest technology that is expected to anchor the Israel Air Force for years to come.

Despite taking years to produce, a high price tag, and suffering numerous setbacks, Israel’s purchase of the 17 additional F-35s appeared to be a show of confidence in the plane and its abilities.

Israel receives over $3 billion a year from the US in military aid, and early this year the two countries agreed on a new aid package that will see Israel receive $3.8 billion annually through 2028, the vast majority of which must be used on purchases from American defense companies.

Times of Israel staff contributed to this report.