WASHINGTON — Secretary of State Mike Pompeo on Thursday dismissed as “bizarre” and “outrageous” a Democratic senator’s question about whether President Trump’s business interests could be affecting his administration’s foreign policy.

In an exchange before the Senate Foreign Relations Committee, Mr. Pompeo grew testy when Senator Tom Udall, Democrat of New Mexico, asked how Mr. Trump’s finances might impact his foreign policy decisions.

It was the second time in two days that the nation’s new chief diplomat displayed a flash of anger during congressional testimony.

“Given that the president refuses to disclose his tax returns, how can you assure the American people that American foreign policy is free of his personal conflicts of interest?” Mr. Udall asked.