“We are near you, where you can’t even imagine,” he said. “We are ready. We are the man of this arena.”

While the possibility of a war between Iran and the United States is considered extremely low, political analysts worry that escalating threats could lead to something more serious.

General Suleimani’s words and actions are closely scrutinized because he is regarded as one of Iran’s most cunning and autonomous military figures, in charge of its intelligence gathering and covert military operations.

“His fire-breathing retort to Trump is important and worrisome,” said Cliff Kupchan, chairman of the Eurasia Group, a political risk consultancy in Washington.

“Suleimani is directly mocking the U.S. president, and he lambastes U.S. policy,” Mr. Kupchan said. “Suleimani is telling Trump to watch his words, reminding him that Iran has both power across the Middle East and potent capability for asymmetric warfare. That’s an implicit threat against U.S. assets in the Middle East.”

A once-shadowy figure who now enjoys celebritylike status among the hard-line conservatives in Iran, General Suleimani leads the Islamic Revolutionary Guards Corps’ Quds Force, a special forces unit responsible for Iranian operations outside Iran’s borders. Quds is the Persian word for Jerusalem.

The general is known to have the personal backing of Iran’s supreme leader, Ayatollah Ali Khamenei, and is believed to be the chief strategist behind Iran’s military ventures and influence in Syria, Iraq and elsewhere in the region and beyond.