In response, Iran has bolstered its missile capabilities, positioning advanced air defense systems around the Strait of Hormuz while ramping up military activities. Russia and China recently held military naval drills with Iran in the Gulf of Oman, a strategic waterway.

The intelligence community does not yet believe Iran is moving toward a nuclear weapon, according to Director of National Intelligence Tulsi Gabbard.

U.S. Defense Secretary Pete Hegseth has reinforced U.S. military capability in the Middle East with more warplanes, the Pentagon said on Tuesday, amid a more than two-week-old U.S. bombing campaign in Yemen and mounting tensions with Iran.

A senior Iranian military commander has warned that American troops in the region are vulnerable and "sitting in a glass house."

Russia's Foreign Minister Sergei Lavrov discussed with his Chinese counterpart, Wang Yi, the situation on the Korean Peninsula as well as Iran's nuclear program, the Russian foreign ministry said late on Tuesday.

An advisor to Iran's supreme leader said on Monday that Iran will be forced to build a nuclear weapon if the U.S. makes a "mistake" about Tehran's nuclear issue.

Trump warned Iran after sending a letter to revive nuclear talks. With "maximum pressure" back on the table, tensions between the two nations continue to rise.

WASHINGTON (Reuters) - The United States issued fresh Iran-related sanctions on Tuesday targeting six entities and two individuals based in Iran, China and the United Arab Emirates, the Treasury Department said on its website.