Iran claimed it is capable of building a nuclear weapon as Supreme Leader Ayatollah Ali Khamenei vowed a "tooth-breaking" response to the actions of both Israel and the U.S. on Saturday.

A top adviser to Khamenei, Kamal Kharrazi, issued the warning about Iran's nuclear capacity on Friday, saying that the country may be prepared to alter its policies on using nuclear weapons if the nation faces an existential threat.

"If an existential threat arises, Iran will modify its nuclear doctrine, we have the capability to build weapons and have no issue in this regard," Kharrazi told Lebanese media.

General Mohammad Naeini of the Iranian Revolutionary Guard backed up the heated rhetoric on Saturday.

ISRAEL CEASE-FIRE PLAN FOR LEBANON SEEKS TO BYPASS UN, AS US MEDIATORS TRAVEL TO JERUSALEM FOR TALKS

Iran's Supreme Leader, Ayatollah Ali Khamenei says Iran is prepared to deliver a "tooth-breaking" response to Israel and the U.S. (Iranian Leader Press Office/Handout/Anadolu via Getty Images)

"A decisive and strong response will be given to the enemy’s new aggression. The response will be beyond the enemy’s comprehension, strategic, and powerful. The enemy must learn its lesson that it cannot engage in any act of hostility without receiving a crushing response in return," Naeini said.

Naeini's comment came in reference to Israel's Oct. 26 attack on Iran, which targeted critical military infrastructure. That attack from Israel came in response to a wave of 200-some missiles launched from Iran into Israel on Oct. 1.

IRAN AND RUSSIA CLOSE IN ON DEAL AS TEHRAN THREATENS REVENGE AGAINST ISRAEL

Prime Minister Benjamin Netanyahu says Israel may target Iran's nuclear program. (Ma'ayan Toaf, Israel Government Press Office)

Israeli Prime Minister Benjamin Netanyahu signaled on Thursday that Iran’s nuclear program could be Jerusalem’s next target amid Tehran's promises of violence.

The U.S. – Israel’s chief ally in its fight against Hamas, Hezbollah and Iran – has repeatedly warned Jerusalem against hitting Iran’s energy infrastructure, in particular, its nuclear and oil facilities, out of concern it could prompt an outright regional war.

The Foundation for Defense of Democracies (FDD) has analyzed where Iran's nuclear infrastructure is located as Israel mulls a retaliatory attack. (Foundation for Defense of Democracies)

CLICK HERE TO GET THE FOX NEWS APP

Reports this week suggested that Iran could be waiting until after the U.S. presidential election next week, though other reports have said Tehran’s retaliatory strike could come at any time. 

Fox News' Caitlin McFall contributed to this report