The Biden administration announced a new $625 million security assistance package for Ukraine on Tuesday that will include key weapons, ammunition and equipment.

This is the U.S.’ first military aid package to Ukraine since Russia took the escalatory step of annexing four regions of the country. The package includes advanced mobile rocket launcher systems that have been crucial to Ukrainian forces.

The Pentagon said the package contains four High Mobility Artillery Rocket Systems (HIMARS), as well as howitzers, artillery and mortar rounds, and small arms ammunition. This is the first time the U.S. has sent more HIMARS to Ukraine since July. The weapons have allowed Ukrainian forces to strike bridges used to supply Russian troops, AP said.

The U.S. has now sent Ukraine more than $16.8 billion in aid since the start of the Russian invasion, the Pentagon said.