The State Department approved the sale of 500 Patriot PAC-3 missile interceptors to Ukraine for an estimated $2.1 billion, marking a potentially significant new supply of defensive weapons for Kyiv during President Donald Trump’s second administration.

The approval comes as delayed missile deliveries have increased tensions between Ukraine and the United States. Trump announced a diesel deal with Russia and criticized Ukrainian President Volodymyr Zelenskiy over Ukraine’s unwillingness to halt attacks against Russian refineries.

Ukraine has repeatedly said it urgently needs additional interceptors to counter growing waves of Russian missiles. The Patriot system is described as the most effective weapon available to Ukraine for defeating ballistic missiles traveling at high speeds.

The need was highlighted by another deadly series of Russian attacks. On Thursday, a Russian drone strike killed at least 14 people on a crowded rail platform in Dnipro, while daytime attacks on two other provincial cities killed five people.

A missile strike later that evening killed one person in Kyiv, according to officials. Zelenskiy said Monday that Ukraine had already waited almost a month for Washington to approve critical missile supplies as Russia increased attacks on civilian and energy infrastructure.

Despite the urgency surrounding the approval, the 500 Patriot interceptors are unlikely to reach Ukraine quickly. Weapons sales commonly take years to complete, and the missiles covered by this sale have not yet been manufactured.

Two people briefed on the decision said deliveries are not expected until a couple of years into the 2030s. That timetable leaves a considerable gap between the immediate battlefield demand and the projected arrival of the newly produced interceptors.

One of the people said Ukraine’s Ministry of Defense is urging the Pentagon to accelerate the delivery schedule. One possibility would involve providing Kyiv with Patriot interceptors already held in the American arsenal and later replacing them with the newly manufactured missiles.

Ukraine will finance the purchase through several sources. Contributions from Canada, Germany and Norway will be routed through a program called US JUMPSTART, while additional national funds will come from the European Union’s Ukraine Support Loan.

According to the State Department, the financing structure will allow Ukraine to move forward with the purchase. A Pentagon website says the JUMPSTART program uses allied donations to purchase weapons, services and training that support Ukraine’s self defense following Russia’s invasion.

The program was previously used in August to purchase 3,350 air launched cruise missiles valued at $825 million. Those weapons were made by Zone 5 Technologies and CoAspire.

Lockheed Martin will serve as the principal contractor for the Patriot interceptor sale. The approval arrives as the United States supplies large quantities of weapons to allies while also using munitions in its own military operations in Iran.

Those competing demands have raised concerns about American inventories of critical air defense and precision guided weapons. Pentagon negotiators are pressing contractors to increase production more quickly, with tentative production agreements reached earlier this year playing a central role in efforts to boost missile output.

In July, the U.S. Army awarded Lockheed Martin a contract worth up to $58.6 billion to produce Patriot interceptor missiles. Lockheed said that agreement would help the company fulfill its pledge to triple PAC-3 MSE production capacity by the end of 2030.

The company also plans to increase employment at its Camden, Arkansas, plant by 50%, raising the workforce from about 1,200 people to roughly 1,850. Lockheed previously announced that annual production of Patriot PAC-3 missile interceptors would rise to 2,000 units.

The sale therefore carries substantial firepower and a substantial price tag, but production and delivery remain the decisive obstacles. Ukraine has Washington’s approval for the missiles, while the proposed delivery timeline still stretches years beyond Kyiv’s stated immediate need.