DUBAI, United Arab Emirates — U.S. President Donald Trump said Sunday that Iran proposed negotiations after his threat to strike the Islamic Republic over its bloody crackdown targeting demonstrators there, a move coming as activists said the death toll in protests rose to at least 544.

Trump and his national security team have been weighing a range of potential responses against Iran including cyberattacks and direct strikes by the U.S. or Israel, according to two people familiar with internal White House discussions who were not authorized to comment publicly and spoke on condition of anonymity.

“The military is looking at it, and we’re looking at some very strong options,” Trump told reporters Sunday night. Asked about Iran’s threats of retaliation, he said: “If they do that, we will hit them at levels that they’ve never been hit before.”

Speaking later on Air Force One, Trump said that his administration was in talks to set up a meeting with Tehran, but cautioned that he may have to act first as reports of the death toll in Iran mount and the government continues to arrest protesters.

“I think they’re tired of being beat up by the United States,” Trump said. He added, “Iran wants to negotiate.”

He added: “The meeting is being set up, but we may have to act because of what’s happening before the meeting. But a meeting is being set up. Iran called, they want to negotiate.”