TEHRAN, Oct. 13 (Xinhua) -- Iran's supreme leader Ayatollah Ali Khamenei on Sunday vowed that Iran will never give in to the pressures by its enemies, Tasnim news agency reported.

Khamenei slammed the United States and Israel for what he called "sucking the blood of nations, warmongering activities, causing catastrophes, and treating other nations with cruelty and suppression."

Khamenei made the remarks in Tehran during a graduation ceremony of students at Imam Hossein University belonging to the Islamic Revolution Guards Corps (IRGC).

"Based on its religious teachings, Iran is duty-bound to counter the enemies and will never capitulate to the United States and various pressures from the adversaries," he was quoted as saying.

Iran has been under heightened U.S. pressure with suffocating sanctions, politically and economically, following the U.S. withdrawal from the Iranian landmark 2015 nuclear deal last year.