TEHRAN: Iran's supreme leader Ayatollah Ali Khamenei said Wednesday that his country remains unbowed by pressure exerted by the United States and its "insults" against the Islamic republic.

"The Iranian nation seeks dignity, independence and progress; that's why pressures by cruel enemies do not affect Iranians," Khamenei said in a speech to a crowd in Tehran.

"The graceful Iranian nation has been accused and insulted by the world's most vicious regime, the US, which is a source of wars, conflicts and plunder," he said, quoted by his office.

"The Iranian nation won't give up over such insults," said Khamenei.

Tehran and Washington have engaged in an escalating war of words following Iran's shooting down of a US drone last week.

Pressure mounted this week with US President Donald Trump announcing sanctions on Khamenei and other top Iranian officials.

The new measures are the latest against Tehran since Trump last year pulled out of a landmark nuclear accord between Iran and world powers.