Donald Trump on Monday defended hush money payments reported by his former lawyer, responding a day after Democratic lawmakers said the U.S. president could face impeachment and jail time if the transactions are proven to violate campaign finance laws.

Trump said on Twitter that Democrats were wrongly targeting “a simple private transaction.” Court filings last week drew renewed attention to six-figure payments made during the 2016 presidential campaign by Trump’s personal lawyer to two women so they would not discuss their alleged affairs with the candidate.

U.S. Representative Jerrold Nadler, who will lead the Judiciary Committee when Democrats take control of the House of Representatives next month, said on Sunday that if the payments were found to violate campaign finance laws it would be an impeachable offense.

His Democratic counterpart on the Intelligence Committee, Representative Adam Schiff, said Trump could be indicted once he leaves office and could face the real prospect of jail time.”

Under U.S. law, campaign contributions, defined as things of value given to a campaign to influence an election, must be disclosed. Such payments are also limited to $2,700 per person.

Earlier this year, Trump acknowledged repaying his former lawyer Michael Cohen for the $130,000 paid to porn star Stephanie Clifford, also known as Stormy Daniels. He previously disputed knowing anything about the payments.