Nearly a dozen American scientists with ties to NASA and nuclear research have died, gone missing, or vanished under unexplained circumstances in the US in the past four years.

Many of those involved have been linked to highly sensitive defence and space programs, prompting calls for briefings from the Pentagon, FBI, NASA and the US Department of Energy.

“These are some of the most advanced scientists, researchers in our nation … and they all just mysteriously disappeared. This is too coincidental,” Congressman Eric Burlinson said.

The mysterious pattern has gained the attention of US President Donald Trump, who recently vowed to get to the bottom of it within the week.

Despite growing speculation online, no official link has been established between the cases. Investigations are ongoing.