The United States is sending Ukraine two NASAMS surface-to-air missile systems, four additional counter-artillery radars and up to 150,000 rounds of 155mm artillery ammunition as part of its latest weapons packages for Ukraine, the Pentagon said on Friday.

The assistance package, worth about $820 million, was broadly announced by U.S. President Joe Biden on Thursday in Madrid following a gathering of NATO leaders that was focused on Russia's invasion of Ukraine.

The Pentagon offered more details on Friday as it formalized the announcement, and said the latest round of security assistance also included additional ammunition for High Mobility Artillery Rocket Systems (HIMARS).

The new U.S. aid is meant to bolster Kyiv as it confronts heavy pounding by Russian artillery. Russia's stepped-up campaign of long-range missile attacks on Ukrainian cities has come as its forces have ground out success on the battlefield in the east, with a relentless assault to try to force Kyiv to cede two provinces to separatists.

Including the latest rounds of assistance, the United States has now committed approximately $6.9 billion since Russia forces rolled into Ukraine on Feb. 24 and brought full-scale war back to Europe.