But there were no incidents on Tuesday as the Lincoln's battle group crossed through the narrow strait, which Iran has threatened to close in retaliation for tighter Western sanctions.

Several U.S. choppers flanked the carrier group throughout the voyage from the Gulf. Radar operators also picked up an Iranian drone and surveillance helicopter in Iran's airspace near the strait, which is jointly controlled by Iran and Oman.

The Lincoln entered the Gulf last month amid heightened tensions with Iran. It is scheduled to begin providing aiding the NATO mission in Afghanistan starting Thursday.