The State Department on Friday approved the possible sale of 500 Patriot air defense missiles to Ukraine, NBC News, CNN and the BBC report. The deal is worth an estimated $2.1 billion.

No American money is involved, the department said. Ukraine will pay with donations from Canada, Germany and Norway, CNN and the BBC report, along with a loan from the European Union. The missiles are the PAC-3 MSE type, the most advanced Patriot now in use, CNN says. They are one of the few weapons that can shoot down ballistic missiles.

Ukrainian President Volodymyr Zelensky welcomed the news but said the missiles are needed now. "It has been stipulated that deliveries may begin ONLY IN A FEW YEARS," he wrote on X, CNN reports. He asked for 100 interceptors a month this winter while the new missiles are built.

The department's release did not say when the missiles would be delivered, CNN reports. The BBC says the order is understood to be for newly built missiles, so a fast delivery is unlikely. Only about 600 Patriot missiles are made each year, the BBC reports, citing the Pentagon. A global shortage has grown because of their use in the war with Iran, the BBC says.

The approval follows weeks of strain between Washington and Kyiv, the outlets report. Zelensky had accused the Pentagon of delaying missiles that other countries bought for Ukraine, NBC News reports. He says Russia has stepped up attacks on Ukraine's power grid ahead of winter, the BBC reports.

What we know: The State Department approved a possible $2.1 billion sale of 500 Patriot missiles to Ukraine.
What we don't: When the missiles will be delivered.