TEHRAN — Iran’s hard-line authorities organized nationwide rallies on Friday to denounce the Trump administration’s withdrawal from the 2015 nuclear agreement, burning American flags and warning that Europe might further sabotage the accord.

The reaction reflected the view held by many hard-liners that the American withdrawal had vindicated their suspicions that Westerners were treacherous.

The anger on display in Tehran and other cities also reinforced the possibility that Iran would now abandon the agreement as well, restarting the nuclear-fuel enrichment that it had halted.

Ayatollah Ahmad Khatami, a well-known hard-liner who leads the Friday Prayer services in Tehran, admonished fellow citizens against making any deals with foreigners “since they cannot be trusted.”