Sen. Lindsey Graham (R-SC) called out entrepreneur Elon Musk on social media Wednesday afternoon over his remarks on Russia’s invasion of Ukraine, and he quickly received a response from the multi-company executive.

Graham also took an apparent shot at Tesla over Musk’s remarks, suggesting that lawmakers should revisit tax credits for electric vehicles.

Graham’s remarks come after Musk proposed earlier in the week that the will of the people who live in Donbas and Crimea should decide whether they stay part of Ukraine or whether they join Russia.