The U.S. State Department has approved a possible sale of Apache helicopters, related equipment and missiles worth $3.5 billion to South Korea, the Pentagon said on Monday.

“The proposed sale will enhance the Republic of Korea’s ability to meet current and future threats by providing a credible force capable of deterring adversaries and participating in regional operations,” the Defense Security Cooperation Agency said in a statement.

According to the Pentagon, Boeing and Lockheed Martin will be the main contractors in the deal.

Although the State Department has approved the sale to South Korea, Congress must still sign it. The deal was announced on the same day that the U.S. and South Korea began their annual joint military exercises.

The news of the sale also came against the backdrop of growing tensions on the Korean peninsula over North Korea’s growing nuclear arsenal.

About 19,000 South Korean military personnel are taking part in the Ulchi Freedom Shield exercises, which are scheduled to run until August 29. The US has not disclosed the number of soldiers participating. The war-simulating drills and field exercises are intended to increase the allies’ preparedness against a North Korean attack.

“As we have seen in Ukraine and the conflicts in the Middle East, war can break out at any time,” said South Korean President Yoon Suk Yeol, explaining the necessity of the exercises. The South Korean head of state described North Korea as “the most reckless and irrational country in the world.”

North Korea regularly condemns the annual joint exercises and accuses the US and South Korea of ​​practicing for an invasion of North Korea.

Pyongyang justifies its growing weapons program by saying it wants to “maintain the balance of power and prevent war by accumulating the greatest possible deterrence.”

North Korean leader Kim Jong Un held a grand ceremony in Pyongyang earlier this month to deliver 250 nuclear-capable missile launchers, reportedly intended for front-line military units.

Some information for this report comes from Reuters, The Associated Press and Agence France-Presse.