As the deadline for a preliminary Iranian nuclear deal approaches, U.S. forces are in the midst of a massive military exercise in the Persian Gulf, according to U.S. Central Command (CENTCOM) officials.

The exercise, named Eagle Resolve, involves 3,000 military personnel including "air, land, sea and special operations components," and has been taking place off Iran's southern coast, in Kuwaiti waters, since March 8, running through the end of the month, reported The Washington Free Beacon.

The United States, along with Britain, France, Russia, China and Germany, have set a March 31 deadline to reach a framework agreement with Iran over its nuclear program. A final deadline has been set for the end of June.

It's the "biggest [operation] to date" and is meant to improve the military's response time should an incident occur, according to a CENTCOM exercise readout provided to the Free Beacon. The exercises also serve as an opportunity for various U.S. military branches to practice tactical moves from the land, sea and air.

"Eagle Resolve 2015 will consist of a week-long series of simulated 'injects' to exercise participants' ability to respond as a multinational headquarters staff, followed by a series of tactical demonstrations of land, maritime, and air forces from several nations," CENTCOM said in a fact sheet given to the Free Beacon. "The exercise ends with a senior leader seminar to foster an environment for commanders to discuss issues of regional interest."

The exercises are focusing on air defense concepts, border security and counter-terrorism operations, as well as consequence management. Some exercises conducted include helicopter drills such as ship-based search and seizure operations, and forces plan to conduct amphibious landings, the official told the Free Beacon.

CENTOM insisted that the exercises aren't meant to send a message to Iran and have nothing to do with the nuclear negotiations, noting that planning for the exercise began over a year ago.

"The exercise is not intended as a signal to Iran," a CENTCOM official told the Free Beacon Sunday. "If there's any message at all, it's that all participants have a common interest in regional security."

"The focus of the exercise is on bolstering capabilities useful in a wide range of scenarios to help preserve and bolster regional security, with simulated portions of the exercise based on a fictional adversary."

But with the timing and location of the exercises, it's not hard to imagine which fictional adversary CENTCOM has in mind.

Iran has been boosting its military strength and showing off its might over the past few months, even vowing to unleash suicide attacks and drone strikes to "destroy the U.S. Navy" in the event of a confrontation. Just this past weekend, Iranian Supreme Leader Ayatollah Khamenei shouted "Death to America!" along with the crowd as he derided sanctions against Tehran.