US President Donald Trump maintains his nationalist, anti-Democrat, media-baiting rhetoric played no role in the spate of attempted mail bomb attacks, instead launching a fresh offensive against the “hateful” media.

In his initial response to the bombs mailed to 13 Democrats, Trump critics and media organisation CNN, Mr Trump said political violence of any kind should never be allowed to take root in the US. He then insisted he was committed to doing “everything in his power” as President to stop it.

“Americans must unify and we must show the world that we are united together in peace and love and harmony as fellow American citizens,” Mr Trump said at the White House during a young black leadership summit.

The FBI on Friday (local time) arrested suspect Cesar Altier Sayoc and charged him with five federal crimes. He has been a social-media supporter of Mr Trump’s denigration of Democrats and ‘fake news’ conspiracy theories.

But Mr Trump still blamed the US “mainstream media” for the wave of mail bombs.

Mr Trump asked: “Who gets attacked more than me?” adding no matter what he did, “media networks” would make him look “bad”.

“There’s no blame. There’s no anything,” Mr Trump said, denying suggestions that his rhetoric, sometimes casually endorsing violence, played any role in the failed bomb plot.

He also claimed he had “toned it down” and that he “could really tone it up”.

The comments came after the President had blamed the media on Twitter.

“A very big part of the Anger we see today in our society is caused by the purposely false and inaccurate reporting of the Mainstream Media that I refer to as Fake News. It has gotten so bad and hateful that it is beyond description,” he said.

“Mainstream Media must clean up its act, FAST!”

Mr Trump also lamented how the “bomb stuff” affected him politically – and could also hit his fellow Republicans’ chances in the looming midterm elections.

Republicans are doing so well in early voting, and at the polls, and now this “Bomb” stuff happens and the momentum greatly slows – news not talking politics. Very unfortunate, what is going on. Republicans, go out and vote!

— Donald J. Trump (@realDonaldTrump) October 26, 2018

Earlier in the week, some Republicans and right-wing commentators had even suggested the bombs may have been a “false flag” attack by left-wingers.

Political critics, including The Washington Post, said Mr Trump’s contrasting reactions fitted a pattern of blame-shifting and casting doubt on the facts when confronted with a politically harmful story.

“Right away he says some of the things that his critics and most of the people would expect from a President, but also doesn’t really like the idea of admitting he might have some culpability or that his allies might have some culpability,” Washington Post writer Aaron Blake said.

Obama takes Trump to task in fiery speech

Former president Barack Obama unleashed a fierce criticism of MrTrump’s presidency in a fiery speech in Milwaukee, accusing Mr Trump and Republicans of “making stuff up”.

Former President Barack Obama campaigns for Democratic candidates during a rally in Wisconsin. Photo: Getty

The speech on Friday was one of Obama’s sharpest and most direct takedowns of Mr Trump’s presidency, although the former president was careful to never mention the President by name.

During the speech to drum up support for Democratic candidates, including Senator Tammy Baldwin and Tony Evers’ campaign, Mr Obama said Mr Trump’s comment that he would pass a tax cut before the November election was a lie.

Mr Obama told the crowd at a Milwaukee high school gymnasium that “Congress isn’t even in session! He just makes it up!”

At one point Mr Obama said: “Here’s the thing. Everything I say you can look up.”

However, Mr Obama did not reserve his criticism to Mr Trump, adding Republicans were also lying when they claimed they wanted to protect people with pre-existing health conditions while simultaneously trying to repeal the Affordable Care Act.

“What we have not seen before … is [sic} politicians just blatantly, repeatedly, baldly, shamelessly, lying. Making stuff up,” Mr Obama said.

-with AAP