The United States is set to send Ukraine more ammunition for the country's stressed air defense systems, as well as more long-range missiles to help keep Russian forces at bay.

The Pentagon on Wednesday formally announced a two-part security assistance package for Ukraine, valued at just over $2.3 billion.

The initial aid includes missiles, rockets and artillery from U.S. stockpiles, valued at up to $150 million.

Some of the key capabilities include more missiles for Ukraine's HAWK air defense systems and ammunition for its High Mobility Artillery Rocket Systems, or HIMARS.

It will also include artillery rounds, mortar rounds; Tube-Launched, Optically Tracked, Wire-Guided (TOW) missiles; and Javelin anti-armor systems.

The second part of the package, valued at about $2.2 billion, will be used to purchase missiles for Ukraine's Patriot missile defense systems and more National Advanced Surface-to-Air Missile Systems (NASAMS). Those systems will need to be assembled and will be delivered at a later date.

The formal announcement of the aid package comes a day after U.S. Defense Secretary Lloyd Austin hosted Ukrainian Defense Minister Rustem Umerov at the Pentagon.

"Ukraine is in a tough fight," Austin told Umerov ahead of their meeting. "The Kremlin continues to intensify its bombardment of your cities and civilians."

"Make no mistake," Austin added. "Ukraine is not alone, and the United States will never waver in our support."

The announcement of the new U.S. aid package comes a week before the U.S. hosts a NATO summit where more military support for Ukraine in the face of Russia's ongoing invasion is to top the agenda.

"The most important deliverable at the upcoming NATO summit is precisely what Secretary Austin was referencing, and that is hardware: artillery shells, air defense interceptors, other kinds of weaponry that the Ukrainians need to defend themselves," said Charles Kupchan, senior fellow at the Council on Foreign Relations.

"If the NATO summit should showcase anything, it is the continued flow of assistance and the continued flow of assistance over the long run," Kupchan told VOA. "Because I think the message here is that the Russians cannot wait out Ukraine and cannot wait out the West."

For the moment, however, Ukrainian defense systems are being pushed to their limits by an unrelenting Russian assault.

Ukrainian officials said Wednesday at least five people were killed and another 53 wounded in Russian missile and aerial drone attacks on the southeastern city of Dnipro.

In the northeastern region of Kharkiv, officials said a Russian attack killed one person and injured 14 others. The attack there also damaged several homes and some businesses.

Ukraine's air force said the Russian attack involved three Iskander-K cruise missiles, four guided missiles and five aerial drones.

The military said its air defenses shot down five of the missiles and all of the drones.

Russia's defense ministry said Wednesday it destroyed five Ukrainian aerial drones over the Belgorod region, four drones over Bryansk and another drone over the Moscow region.

Vyacheslav Gladkov, the regional governor of Belgorod, reported at least two people were injured in separate villages because of the Ukrainian attack.

Officials in Bryansk said there were no injuries or damage from the downed drones.

Meanwhile, renewed efforts to mediate an end to the war appear to have stalled.

According to Turkish officials, Turkish President Recep Tayyip Erdogan on Wednesday spoke with Russian President Vladimir Putin and offered to act as a go-between in negotiations with Ukraine.

But the Tass news agency reported late Wednesday that Russia rejected the Turkish overture.

"No, it's not possible," Tass quoted Russian spokesman Dmitry Peskov telling a television interviewer.

Putin also raised Ukraine with Chinese leader Xi Jinping in Astana, Kazakhstan, where the two spoke during a meeting of the Shanghai Cooperation Organization.

Russian officials said the two leaders called out the futility of any peace talks with Ukraine, which sought to sideline Russian involvement.

The meeting between Putin and Xi is the second in almost as many months.

The two last met face-to-face in May, during Putin's visit to Beijing.

VOA's Kim Lewis contributed to this report. Some information for this story was provided by Reuters, Agence France-Presse and The Associated Press.