Iran’s supreme leader vowed Saturday to give a “crushing response” to Israel’s attacks on Iranian military and missile defense sites, saying they would “not go unanswered” and hinting at a potential role for Iranian-backed groups in any reprisal.

Ayatollah Ali Khamenei issued the warning on Saturday after Israel struck Iran last week, killing at least five people.

Iran’s Supreme Leader Ayatollah Ali Khamenei on Saturday issued a warning to the United States and Israel, and said that both countries will “receive a crushing response” for their actions against Iran.

Threat by supreme leader raises concerns of wider regional conflict just ahead of the American presidential election this Tuesday.

Iran's supreme leader, Ayatollah Ali Khamenei, warned on Saturday of a "crushing response" to Israel and the US following recent attacks on Iranian targets. The news came as the World Health Organization said four children were among six people wounded in a strike on a polio vaccination centre in northern Gaza.

His comments came as the Pentagon said it would send additional fighter jets and destroyers to the Middle East.

"The enemies, whether the Zionist regime or the United States of America, will definitely receive a crushing response to what they are doing," Khamenei said.

Ayatollah Ali Khamenei's speech comes as rockets fired from Lebanon injured 11 people in central Israel, according to Israeli emergency services.

Ayatollah Ali Khamenei warns Israel and the U.S. of 'a crushing response' over attacks on Iran and its allies as regional tensions rise.

Iran is planning a complex attack on Israel, which may include missiles with high-powered warheads, according to a Monday Wall Street Journal report, citing Arab and Iranian officials. The report noted that the Iranian army would also be involved in this potential round of attack.