WASHINGTON (NEXSTAR) – U.S. senators are warning the U.S. has been involved in Russia’s war against Ukraine since the beginning, but not in a way many think.

“Russian weapons using American technology are killing and maiming Ukrainians,” U.S. Sen. Richard Blumenthal, (D-Conn.) said during a committee hearing Tuesday.

Blumenthal said he saw evidence of this during his recent trip to Ukraine.

“President Zelenskyy told me how cutting off Russia’s supply of these components is crucial to Ukraine’s defense,” he said.

The hearing focused on how U.S. companies design and develop the majority of microchips and other technologies found in Russian weapons.

“They know that it’s happening,” said James Byrne, who leads research of these weapons at the Royal United Services Institute. “They know it’s a significant issue.”

The U.S. has imposed sanctions on Russia that aim to prevent all of this, but U.S. Sen. Ron Johnson (R-Wis.) said sanctions don’t work.

“You plug one hole, another hole is going to be opening up,” Johnson said. “It’s gonna be whack-a-mole.”

Byrne told Johnson the sanctions are still better than nothing.

“They do stop a huge amount of things that you don’t see,” he said.

Byrne said companies can do more to track and share where their products are going, but Johnson said the problem is U.S. companies largely outsource their computer chip and technology manufacturing to other countries, like China.

“I’m not defending the companies,” Johnson said. “I’m just saying how difficult this is.”

Johnson argues the vicious cycle will continue until the U.S. ramps up its own manufacturing of these parts.