TEHRAN, July 19 (Xinhua) -- A construction site of Darkhovin nuclear power plant in southwestern Iran's Khuzestan province was attacked by U.S. projectiles on Sunday, the Atomic Energy Organization of Iran (AEOI) said.

In a statement published on its official website, the AEOI said the attack took place at 3:39 a.m. local time (2409 GMT), calling it "an aggressive and brutal action" that violates Iran's national sovereignty and international law.

It did not say if there were any casualties or material damage involved in the attack.

Meanwhile, the Navy of Iran's Islamic Revolution Guard Corps (IRGC) said Sunday it stopped two "violating" vessels seeking to cross the Strait of Hormuz through an unsafe route.

In a statement published on the IRGC's official news outlet Sepah News, the navy said four "violating" vessels ignored warnings, turned off their navigation systems, and tried to cause "disruption" in the strait and pass through it through an unsafe route with U.S. support.

It said two of them "had an accident" and were stopped, and the other two were dissuaded from continuing their route.

The navy said the strait is under the full control of its forces, and the sole secure route for transiting the waterway is the one designated by Iran.

No oil, gas and chemical fertilizer can be transported through the strait without coordination with Iran and its permission, it added.

Iran has tightened its grip on the strait since Feb. 28, when it barred safe passage of vessels belonging to or affiliated with Israel and the United States following their joint strikes on Iranian territory.

Over the past days, the United States has launched waves of strikes against Iran, claiming the attacks were in response to the Iranian armed forces' targeting of vessels in the strait, and aimed at "degrading Iran's ability to threaten commercial shipping."

On Saturday, U.S. Central Command said U.S. forces had completed the eighth round of strikes against "Iranian military coastal surveillance and air defense facilities, maritime capabilities, and missile and drone storage sites," with more than 50,000 U.S. troops in the Middle East remaining "highly vigilant."

Iran has responded with waves of missile and drone attacks targeting U.S. bases and facilities in the region.