Sean Spicer

Spicer's choice of words while comparing Hitler and Syrian president Bashar al-Assad was widely condemned.

On Wednesday, speaking at a forum at the Newseum, Spicer called the incident "my mistake" and "my bad."

He said his original comments were "inexcusable and reprehensible."

Spicer brought up Hitler at Tuesday afternoon's press briefing, and then made repeated, failed attempts to clarify.

"I mistakenly used an inappropriate and insensitive reference about the Holocaust and there is no comparison," he said. "For that I apologise. It was a mistake to do that."

Critics pointed out gas was used to kill Jews and others in the Holocaust.

Mr Spicer had been criticising Russia's support for the Syrian government.

The White House says Russia has been trying to deflect blame for a chemical weapons attack that killed 89 people.

This was in an effort to shame Russia's alliance with Syrian President Bashar al-Assad and his use of chemical weapons.

The comment was immediately decried and after a series of attempts to clear up his words, Spicer apologized in an exclusive interview with CNN's Wolf Blitzer.

Namely, White House press secretary Sean Spicer said Trump wasn't referring to wiretapping when he tweeted about wiretapping.

"I think there's no question that the Obama administration, that there were actions about surveillance and other activities that occurred in the 2016 election," Spicer said. "The President used the word wiretaps in quotes to mean, broadly, surveillance and other activities."

Shree Chauhan, 33, challenged Mr Spicer as he was shopping, asking: "How does it feel to work for a fascist?" - referring to President Donald Trump.

Mr Spicer said: "It's such a great country that allows you to be here."

Ms Chauhan videoed the encounter and posted it online, drawing 300,000 views since Saturday.

She has been attacked online since posting the video, with critics branding her "vile" and accusing her of harassment.

After expressing concern about Wikileaks' release of documents allegedly revealing CIA surveillance techniques, Spicer quickly muddled his message.

He connected the latest WikiLeaks document dump to surveillance efforts under the Obama administration, days after President Donald Trump's leveled his unsubstantiated claim that President Barack Obama tapped the GOP candidate's phones during the 2016 campaign.

Spicer called staff into his office last week to reiterate his frustration with the leaks, sources with knowledge of the matter said. He informed them that the use of encrypted texting apps, like Signal and Confide, was a violation of the Federal Records Act.

Then, with White House counsel Don McGahn standing by, Spicer asked his staff to provide him with their cell phones so he could ensure they were not using those apps or corresponding privately with reporters.