BELLINZONA, Switzerland — In a second major softening of American policy toward Iran in recent days, Secretary of State Mike Pompeo said Sunday that the Trump administration was ready to negotiate with the country’s clerical leaders with “no preconditions.”

The statement followed President Trump’s comment last week that he was ready to talk to Iranian leaders and was not seeking regime change, overruling a longtime goal of his national security adviser. Mr. Pompeo’s statement also recalibrated his earlier position that the United States would not lift sanctions on Iran unless it complied with a dozen sweeping demands, suggesting that those demands could be part of negotiations instead of preconditions.

Iran’s leaders consider the demands unacceptable.

Tensions between the United States and Iran have escalated sharply in recent weeks, raising fears that the two countries were edging toward war. The less combative language does not change the fact that the Trump administration has tightened economic sanctions on Iran, ordered 1,500 additional troops to the Persian Gulf and revised military plans against Iran.

Even in opening the door to talks, Mr. Pompeo said the United States would continue to try to counter Iran’s support of groups in the Middle East that undermine American interests.