Iran’s underground nuclear enrichment site at Fordo was struck again on Monday, Iranian state television reported, a day after the United States bombed the facility using heavy bunker-buster bombs in a major escalation of the ongoing conflict.

Experts warned that worldwide efforts to contain the spread of nuclear weapons by peaceful means would be at stake in the days ahead, while fears of a wider regional conflict loomed large.

Vice President JD Vance clarified that the U.S. is not at war with Iran, but is at war with the country’s nuclear weapons program. Vance spoke with moderator Kristen Welker on NBC News’ “Meet the Press” Sunday. “We’re not at war with Iran,” Vance said, per NBC News. “We’re at war with Iran’s nuclear program.”