"Those European countries which are stepping in the US shoes should know that such companionship is not wise and rational and is a kind of stupidity," Ayatollah Khamenei said, addressing a large number of people in Bojnourd city on Wednesday.
"The European states should know that companionship with the US will yield no results but the Iranian nation's disgust (at them)," he added.
Washington and its European allies accuse Iran of trying to develop nuclear weapons under the cover of a civilian nuclear program, while they have never presented any corroborative evidence to substantiate their allegations. Iran denies the charges and insists that its nuclear program is for peaceful purposes only.
Tehran stresses that the country has always pursued a civilian path to provide power to the growing number of Iranian population, whose fossil fuel would eventually run dry.
Despite the rules enshrined in the Non-Proliferation Treaty (NPT) entitling every member state, including Iran, to the right of uranium enrichment, Tehran is now under four rounds of UN Security Council sanctions for turning down West's calls to give up its right of uranium enrichment.
After the UN Security Council ratified a sanctions resolution against Iran on June 9, 2010, the United States and the European Union imposed further unilateral sanctions against the Islamic Republic over its nuclear program, mostly targeting the country's energy and banking sectors.
Tehran has always dismissed West's pressures, and stressed that sanctions and embargos merely consolidate Iranians' national resolve to continue the path of progress.