The United States on Sunday said it would send an advanced anti-missile system to Israel - and US troops to operate it - in a bid to bolster the country's air defences following missile attacks by Iran.

US President Joe Biden said he was sending the system "to defend Israel".

Pentagon spokesperson Pat Ryder said the deployment of a Terminal High-Altitude Area Defense (THAAD) battery would augment Israel's integrated air defence system.

"It is part of the broader adjustments the US military has made in recent months, to support the defence of Israel and protect Americans from attacks by Iran and Iranian-aligned militias," Ryder said in a statement.

Iran's Foreign Minister Abbas Araqchi warned earlier on Sunday the United States was putting the lives of its troops "at risk by deploying them to operate US missile systems in Israel."

"While we have made tremendous efforts in recent days to contain an all-out war in our region, I say it clearly that we have no red lines in defending our people and interests," Araqchi posted on X.

Iran launched missiles and drones at Israel in April.

Then on October 1, Iran fired more than 180 ballistic missiles at Israel amid an escalation in fighting between Israel and Iran-backed Hezbollah in Lebanon.

Many were intercepted in flight but some penetrated missile defences.

Israel has vowed to retaliate against Iran for that October missile attack. (Reuters)