WASHINGTON — Iran’s president declared on Wednesday that the country would stop complying with two of its commitments under the Iranian nuclear deal, pushing the growing confrontation between Washington and Tehran into new and potentially dangerous territory.

The announcement by President Hassan Rouhani came exactly a year after President Trump withdrew entirely from the 2015 agreement, which limited Iran’s capacity to produce nuclear fuel for 15 years.

But Mr. Rouhani did not follow Mr. Trump’s path and renounce the entire agreement. Instead, he notified European nations that he was taking some carefully calibrated steps, and that he would give Europe 60 days to choose between following Mr. Trump or saving the deal by engaging in oil trade with Iran in violation of American unilateral sanctions.