Two days before the anniversary of the landmark nuclear agreement reached between Iran and six world powers led by the United States, a top U.S. military commander says Iran has not changed its behavior, as five Iranian patrol boats took turns shadowing a U.S. Navy warship he was visiting in the Persian Gulf.

Army General Joseph Votel, who leads U.S. Central Command, said while the deal has frozen Iran’s nuclear weapons program for a time, the activities of Iran’s Revolutionary Guard forces still concern him in the Persian Gulf and beyond. Among those activities: capturing 10 U.S. Navy sailors at gunpoint when their vessels drifted into Iranian territorial waters in January.

“Their general activities that we see out here in the Gulf have not changed as a result of the [nuclear agreement]... and really as we’ve seen much more broadly around the region,” Votel said. He spoke to a small group of reporters during a visit aboard USS New Orleans (LPD-18) in the Persian Gulf as the amphibious ship transited the Strait of Hormuz.

The 684-foot warship was leaving the Persian Gulf with a crew of 1,100 including 650 Marines, following nearly five months of operations during a planned seven-month deployment.  

Votel said Iran should be taken to task for capturing the Navy sailors before releasing them a day later.

“I think they should be held accountable for the way they conducted themselves,” Votel said, but he added that it was not up to him to determine what that punishment should be.

Had the roles been reversed, the outcome would have been very different, Votel said.

“If we came across a [disabled] ship, a small vessel in the area, we would try to assist it, we certainly wouldn’t board it against their will.”

A U.S. Navy investigation recently determined that Iran violated international law for its actions in subduing the American crew.

During the general’s visit to USS New Orleans, five Iranian patrol craft approached the ship. The Iranian vessels included one Houdong-class missile boat, identified by U.S. Navy sailors as P313-6 Shams, capable of launching four anti-ship missiles or firing its two 30 mm cannons. Three other Iranian patrol boats had .50 cal machine guns mounted as well as two rows of multiple rocket launchers.

The missile boat sailed within 500 yards of the U.S. ship.

Lt. Forrest Griggs, an operations officer, said one of the Iranian patrol boats raced up and cut its engines near the USS New Orleans' escort ship, USS Stout, a guided-missile destroyer. 

"I would prefer they not cut in front of our vessels," he said.

While some sailors characterized Iran's behavior Monday as harassment, the general was more measured.   

Votel called the incident "normal activity." Officials with Central Command, responsible for military operations in the Middle East, called the interaction "safe, routine and professional and without incident."  

Fox News was present aboard USS New Orleans and witnessed the Iranian interactions and can confirm the Iranian ships did not appear to show hostile intent.

But similar Iranian warships launched unguided rockets 1,500 yards from the American aircraft carrier USS Theodore Roosevelt in December -- also during a transit of the Strait of Hormuz.

U.S. Navy ships cross the strait 250 times a year. 90 percent of those transits are “characterized as safe,” According to Cmdr. Bill Urban, a spokesman for the U.S. Navy’s 5th fleet, responsible for maritime operations in the Persian Gulf.

It’s those other 10 percent of Iranian interactions with U.S. Navy warships that have Votel concerned.

“In a relatively compressed space here, there is great opportunity for miscalculation,” the general said. “Our people don’t always have a lot of time to deal with those interactions, what we have probably learned here today is that it’s measured in minutes.”

Urban says the U.S. Navy has rendered assistance to four Iranian-flagged vessels in the last two months, 11 since 2012.

Appearing before the Senate Armed Service Committee in March, Votel told lawmakers the United States should “expose” Iran for the destabilizing role it was playing in the Middle East.

When asked about those comments Monday aboard USS New Orleans, Votel said: “Iran has to be held accountable for the type of influence they are trying to create, whether it is instability in Yemen, whether it is their backing of the Syrian regime, who attacks their own people who drops barrel bombs on them... [and] causing significant refugee problems.”

Iran tried illegally to obtain nuclear equipment in the months after the nuclear agreement was reached last year, The Wall Street Journal reported, citing German intelligence officials. In January, he U.S. and European Union lifted some sanctions against Iran as part of the deal.

When asked if Iran had been held accountable for taking the U.S. Navy sailors hostage, Votel said, “I don’t think so.”

Lucas Tomlinson is the Pentagon and State Department producer for Fox News Channel. You can follow him on Twitter: @LucasFoxNews