A new package of U.S. military assistance to Ukraine, which will be announced later this week, will include four more HIMARS multiple launch rocket systems, U.S. Secretary of Defense Lloyd Austin has said.

"It will include four more HIMARS, advanced rocket systems, which the Ukrainians have been using so effectively and which have made such a difference on the battlefield," Austin said during opening remarks ahead of the fourth meeting of the Ukraine Contact Group held virtually Wednesday.

The minister said that since the meeting in Brussels, the United States has pledged more than $2.6 billion in security assistance to Ukraine.

Austin said the assistance includes a total of 12 reactive volley fire systems HIMARS to further enhance Ukrainian long-range firepower. The United States also pledged to transfer two NASAMS air defense systems to help Ukraine protect its forces and civilians from Russian missile attacks. The United States is also committing to send more HIMARS munitions, precision-guided artillery munitions and tactical vehicles, and other urgently needed support, according to the official.

He said the United States will continue to provide historic levels of security assistance to help Ukraine defend itself.