The first shipments of the latest round of U.S. military assistance to Ukraine, which includes heavier weapons systems, started arriving in the region over the weekend, according to the Pentagon, writes cbsnews.com.

The recently approved USD 800 million in security assistance includes Howitzer artillery systems, 40,000 artillery rounds, armored personnel vehicles and other weapons.

A senior U.S. defense official said Monday that four flights of shipments from the assistance package arrived in the region over the weekend with a fifth expected in the next 24 hours. The official did not detail which weapons from the recent package landed in the region first.

Pentagon spokesperson John Kirby in a press briefing said the Defense Department expects to start training Ukrainian trainers outside of Ukraine on how to use the U.S.-provided Howitzers in the coming days. The Ukrainian trainers will then return to Ukraine and train more troops.

According to Kirby, the training isn’t expected to take long since the Ukrainians already know how to use artillery systems and merely need to familiarize themselves with the American systems. The Ukrainians use 152mm artillery systems, and the U.S. is providing 155mm artillery systems.