US Navy

The move comes just days after North Korea demonstrated a significant leap forward in their missile program after launching a projectile that achieved "successful" controlled reentry into the Earth's lower atmosphere rather than falling back to the surface, according to a preliminary US intelligence analysis, two US officials tell CNN.

A medical team aboard the USS Dewey examined the helicopter crew and reported no apparent injuries.

A Trump flag was spotted on a military convoy driving outside Louisville, Kentucky, on Sunday. The US Navy confirmed to CNN that the Humvees were being driven by an East Coast Naval Special Warfare unit -- also known as a Navy SEALs unit.

Flying certain flags from military vehicles is allowed, but a blue Trump flag waving in the wind is not one of them.

The breach came after the laptop of an employee at Hewlett Packard Enterprise working on a naval contract was "compromised", the Navy said.

It added that "unknown individuals" accessed the sensitive information on current and former sailors.

The data included names and social security numbers, but the Navy does not currently believe it was misused.

The aircraft were flying in international airspace but "near Iranian airspace."

The Iranians made a radio call to both planes warning them not to enter Iranian airspace and risk being shot down, the official said. The US aircraft never entered Iranian airspace and proceeded without incident.

The Iranians threatened to launch missiles to shoot down the aircraft as part of the threat.

The official, speaking on the condition of anonymity, said three warning shots were fired from a .50 calibre gun on Wednesday (local time) after warning flares did not work.

The incident started with three Iranian vessels, but there was only one Iranian vessel around by the time the warning shots were fired, the official said.

The official added that at one point an Iranian vessel came within 200 metres of a US ship.

Named the railgun, the weapon in question represents a paradigm shift in ballistic technology.

Instead of using gunpowder and explosive charges to shoot a shell from its barrel, it employs vast amounts of electromagnetic energy to zoom a projectile along a set of copper-alloy rails.

Thanks to four small fins on its rear, the hefty round can then be guided toward a moving object — such as an enemy ship, drone or incoming ballistic missile — relying purely on the kinetic energy from its vast momentum to destroy the target.