President Donald Trump challenged former Secretary of State John Kerry Monday for speaking to Iranian leaders as they struggle with tough policies from the Trump administration.

“Iran is being given VERY BAD advice by John Kerry and people who helped him lead the U.S. into the very bad Iran Nuclear Deal,” Trump wrote on Twitter. “Big violation of Logan Act?”

In 2018, Kerry admitted meeting with Iranian Foreign Minister Javad Zarif “three or four times” to discuss Obama’s signature nuclear deal with Iran that Trump ripped up.

“What Secretary Kerry has done is unseemly and unprecedented,” Secretary of State Mike Pompeo said in reaction to the news. “This is a former secretary of state engaged with the largest state sponsor of terror.”

The Logan Act criminalizes unauthorized negotiations between American citizens and foreign governments who have disputes with the United States.

Trump commented after announcing his decision to cut waivers allowing allies to buy Iranian exports of oil.

“Saudi Arabia and others in OPEC will more than make up the Oil Flow difference in our now Full Sanctions on Iranian Oil,” he said confidently.