Iran is readying a massive military exercise in the Persian Gulf that could be used to demonstrate Tehran's ability to block the Strait of Hormuz, CNN reports.

Iran's Islamic Revolutionary Guard Corps (IRGC) could begin the drill within the next 48 hours, CNN reported Wednesday afternoon.

Iran has so far assembled a fleet of about 100 boats, according to a U.S. assessment reported by the network, and hundreds of Iranian troops are expected to take part in the exercise.

ADVERTISEMENT

The possible exercise has raised concerns among U.S. military intelligence officials, according to CNN. Such drills usually happen later in the year, and officials believe the IRGC may be planning for a larger exercise later on.

"We are aware of the increase in Iranian naval operations within the Arabian Gulf, Strait of Hormuz and Gulf of Oman. We are monitoring it closely, and will continue to work with our partners to ensure freedom of navigation and free flow of commerce in international waterways," Navy Capt. Bill Urban, a spokesman for U.S. Central Command, said in a statement.

"We also continue to advocate for all maritime forces to conform to international maritime customs, standards and laws," he added.

Tensions between the U.S. and Iran have risen since May when President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE announced that he would withdraw from the Iran nuclear deal, a 2015 framework seeking to curb Tehran's nuclear ambitions and impose sanctions lifted under the deal.

The U.S. is also seeking to pressure other countries to stop importing Iranian oil by November as it seeks to ramp up pressure on Tehran.

In turn, Iran suggested that it could shut down the Strait of Hormuz, a key shipping lane through which much of the world's oil supply passes, warning that interrupting Iran's oil exports could threaten exports throughout the region.

The U.S. currently has only one warship in the Persian Gulf, the USS The Sullivans, CNN reported.

Updated: 4:36 p.m.