Donald Trump

Just 100 days from the election, Trump has responded in his standard fashion -- dig in, claim he's being treated unfairly and attack back.

But the swift condemnation of Trump's response raises questions about whether this controversy is different from the ones that came before it.

Ghazala Khan said Mr Trump was ignorant about Islam and that he didn't know the meaning of the word sacrifice.

Her husband Khizr Khan attacked the Republican nominee in an emotional speech to the Democratic National Convention on Thursday.

Mr Trump later suggested Mrs Khan may not have been allowed to speak.

The couple's son, US Army Capt Humayun Khan, was killed by a car bomb in 2004 in Iraq at the age of 27.

Ghazala Khan stood silently next to her husband as he attacked Mr Trump in an emotional speech to the Democratic National Convention on Thursday.

Mr Trump suggested she may not have been allowed to speak.

Republicans and Democrats said the Republican candidate's comments were no way to talk of a hero's mother. Mrs Khan said she was upset by his remarks.

Last week her husband Khizr Khan told Democrats Mr Trump had sacrificed "nothing and no-one" for his country.

The billionaire businessman was responding to comments by Khizr Khan, whose son, a US Muslim soldier, was killed in Iraq.

Captain Humayun Khan died in 2004 while trying to stop a suicide bomber outside his camp in Baquba, north-east of Baghdad.

Mr Khan had accused the billionaire of vilifying American Muslims, in a steely rebuke that electrified the Democratic convention on Thursday.

"Of course I'm being sarcastic," Trump said in an interview on Fox News that aired Thursday morning. "You have 33,000 emails deleted, and the real problem is what was said on the emails from the Democratic National Convention."

Trump was referring to the recent hack of the Democratic National Committee, which led to the publication of thousands of emails on WikiLeaks. The emails showed officials criticizing Bernie Sanders during his primary campaign against Hillary Clinton, a time when the DNC claimed it was neutral in the race.

On his campaign trail, he is known to make appalling statements and earning a place in news headlines.

Well, in the latest development, Trump hit a new low. Speaking at a press conference, he urged the Russian government to hack into the US government servers.

Here’s what he said:

“Russia, if you’re listening, I hope you’re able to find the 30,000 emails that are missing. I think you will probably be rewarded mightily by our press.”

Mrs Clinton did not hand over 30,000 emails as part of an investigation into her private email server as they contained private details.

"Russia, if you're listening, I hope you're able to find the 30,000 emails that are missing," Mr Trump said on Wednesday.

"I think you'll be rewarded mightily by our press."

The emails would contain some "beauties", he said. Soon after, he wrote on Twitter that if anyone had the emails, they should hand them over to the FBI.

Two days later, on Sunday, DNC Chairwoman Debbie Wasserman Schultz announced her resignation and now had no major role on the party's convention stage.

Many of the leaked emails indicted that the top DNC officials were actively working against the campaign of Sen. Bernie Sanders and strongly favoring Hillary Clinton over Sanders during the primaries, when they were supposed to be neutral.

The controversy ruined the start of the DNC's national convention in Philadelphia and forced the Wasserman Schultz to resign.

Donald Trump comes out of his convention ahead of Hillary Clinton in the race for the White House, topping her 44% to 39% in a four-way matchup including Gary Johnson (9%) and Jill Stein (3%) and by three points in a two-way head-to-head, 48% to 45%. That latter finding represents a 6-point convention bounce for Trump, which are traditionally measured in two-way matchups.

"I know for certain that Chris would not have wanted his name or memory used in that connection," Mary Commanday wrote in the letter, which was published Saturday. "I hope that there will be an immediate and permanent stop to this opportunistic and cynical use by the campaign."