Donald Trump

Trump, reading from prepared remarks on Thursday night, acknowledged that he sometimes says "the wrong thing" in an astonishing act of contrition that signaled Trump's willingness to break from his characteristic brashness and bare-knuckles style that carried him to victory in the Republican primaries, but risks dooming him in the general election.

The killing of Sylville Smith, which took place in a predominantly African-American part of Milwaukee on Saturday, led to several days of protests.

"We have to obey the laws or we don't have a country," Mr Trump told Fox News after visiting police in the city.

A string of fatal police shootings have sparked demonstrations across the US.

Protesters say the police are too ready to use lethal force against African Americans.

In the latest incident on Saturday, 23-year-old Mr Smith was stopped by police and then fled.

The proposal, outlined in a speech in Ohio, includes temporarily suspending visas from countries with terrorist ties as well as introducing an ideological test for those entering the US.

Though Mr Trump has yet to outline which countries would be included on the list, he told supporters at the rally he would "ask the State Department and Department of Homeland security to identify regions where adequate screenings cannot take place".

In a speech in Ohio, the candidate outlined his plans to combat Islamic extremism, including a new screening test for arrivals to the US.

Applicants will be tested to determine if they share Western liberal values like LGBT and religious tolerance.

Democratic rival Hillary Clinton poured scorn on his plan, labelling it a "cynical ploy".

"This so-called 'policy' cannot be taken seriously," said her spokesman.

The paper said ledgers earmarked $12.7m (£9.8m) in undisclosed cash payments from a pro-Russia political party in Ukraine to Mr Trump's campaign head Paul Manafort between 2007 and 2012.

His lawyer said Mr Manafort had not received any such payments.

Now a few of his critics have seized on the country's Olympic victories to turn the Republican nominee's signature line against him.

Ohio Gov. John Kasich, who alongside Texas Sen. Ted Cruz remains the most prominent GOP holdout on Trump, tweeted Friday night, "Someone said we don't win anymore. Must not be watching Americans swimming in Rio tonight!"

And Trump is having none of it. The problem, he says, is ... The Times.

"The failing @nytimes has become a newspaper of fiction," he tweeted Saturday afternoon about two hours after the story went online. "Their stories about me always quote non-existent unnamed sources. Very dishonest!"

Trump has repeatedly called The Times a "failing" paper in reference to its financial challenges. He routinely calls the media "dishonest."

At a rally in Fairfield, Connecticut on Saturday night, he said "the newspaper is going to hell."

"Literally" was once used, exclusively, to introduce or punctuate a point meant to be taken in literal terms. But by 2013, enough people were using it interchangeably with "metaphorically" that even leading grammar pedants threw up their hands (literally?), and the Merriam-Webster and Cambridge dictionaries expanded their definitions.

"We're going to watch Pennsylvania. Go down to certain areas and watch and study and make sure other people don't come in and vote five times," he said at a rally in Altoona, Pennsylvania. "If you do that, we're not going to lose. The only way we can lose, in my opinion -- I really mean this, Pennsylvania -- is if cheating goes on."

Trump said that Republican leaders in the state "are very concerned" about the possibility of cheating -- adding that "we have to call up law enforcement, and we have to have the sheriffs and the police chiefs and everybody watching."

They said Mr Trump's "divisiveness" and "incompetence" risked drowning the party in November's election.

The letter said that the party should instead focus on protecting vulnerable candidates in elections to the Senate and the House of Representatives.

Former members of Congress are among the signatories of the letter.