Donald Trump is known to play a little fast and loose with the facts at times. So as the president delivered his first State of the Union address on Tuesday, people were keen to check what he was saying was the whole truth.

So great was the interest, however, that non-partisan fact-checking site PolitiFact crashed during his speech.

"Welp ... our website just crashed. Thanks for reading ?!!? We'll keep things up here on Twitter while we see what happened," the website tweeted, citing high web traffic numbers.

The outage came about half-way through the 80-minute address and lasted about five minutes.

The site, which is owned by the non-profit Poynter Institute and run from a reporting team at the Tampa Bay Times, ranked the veracity of Mr Trump's statements from "Mostly True" to "Pants on Fire" wrong.