"Unlike what some people say that a war will break out, we never push the country toward war, but if others want to impose something on the country, we will strongly stand up to it," he said on Wednesday, addressing a group of nurses on the occasion of National Nurse Day, Leader.ir reported.
The remarks came against a backdrop of increasing friction between Iran and the United States following recent escalations in Iraq.
The US military carried out airstrikes on Sunday against the Iran-allied Kataib Hezbollah militia group, an associate of Iraqi paramilitary group Hashd al-Shaabi (Popular Mobilization Forces), in which about 25 fighters were killed, Financial Tribune reported.
Washington accused the group of killing a US civilian contractor and injuring several other American service members in a rocket attack on a coalition military base.
"I, and the people and government of Iran strongly condemn America's crime of attacking Iraq's Hashd al-Shaabi," the Leader said.
The US move aroused anger among the Iraqi people, prompting thousands of protesters and militia fighters to storm the US Embassy in Baghdad in protest on Tuesday.
Consequence of US Crimes
US President Donald Trump said on Tuesday that Iran will be held accountable for lives lost in attacks on any US facilities.
"Iran will be held fully responsible for lives lost, or damage incurred, at any of our facilities. They will pay a very BIG PRICE! This is not a Warning, it is a Threat,” he wrote on Twitter hours after the protests.
Tehran denies any interference in regional countries' domestic affairs.
Ayatollah Khamenei said the anti-US movement in Baghdad is the natural consequence of America's crimes and has nothing to do with Iran.
He urged the US to be logical and figure out the source of these incidents.
"Americans must understand that the people of the region, like in Iraq and Afghanistan, hate them for their crimes and this hatred will manifest somewhere," he said.
He pointed to the US murder of thousands of Iraqi intellectuals and ordinary people, saying such loathing results from these political and security measures and oppression of the people of this region.
"America's attack on Hashd al-Shaabi is in fact avenging the [defeat of] Daesh [the self-styled Islamic State terrorist group]," he said.
The Kataib Hezbollah militia had a key role in the downfall of the IS, the same terrorist group that provided the US with a pretext to station military troops in the region.
Swiss Envoy Summoned
The Foreign Ministry on Wednesday summoned the Swiss envoy representing the US interests in Iran to voice Tehran's protest against the US officials' hawkish statements.
Mohsen Baharvand, an assistant to the foreign minister, asked Markus Leitner to convey Iran's protest to the US along with the message that "Iraq is an independent country and Iraqis are freedom-seeking, nationalist and decent people. The US army has killed at least 25 Iraqi youths and injured countless others without presenting the least evidence of their responsibility [in killing the American citizen]," he told the envoy.
He added that it is natural for the people of Iraq to react to a country that has occupied their land and kills their youths.
Baharvand reiterated that Iran is not a warmongering country, but will not remain idle against any threat or unwise measure, and will defend itself with all its power.