Hillary Clinton's campaign manager, Robby Mook, today called Republican nominee Donald Trump's hinting at classified intelligence briefing information "concerning".

Mr. Trump, meanwhile, has delved deeper into policy than ever before, putting meat on the bones of his immigration, defense and education plans.

In Pennsylvania, Mrs. Clinton continues her lead, 44 percent to Mr. Trump's 39 percent, in a four-way contest, but the race has tightened considerably.

Trump did little to counter the criticism that he lacks detailed policy proposals, particularly regarding the Islamic State group.

Clinton was leading in Pennsylvania, 48 percent to 43 percent, down from her 10-point advantage last month, 52 percent to 42 percent. The Republican defended his preparedness to be commander in chief despite vague plans for tackling global challenges and the Democrat argued that her controversial email practices did not expose questionable judgment. "Sound familiar?" he said drawing a parallel between Trump and Reagan.

"Trump has an ability to manipulate situations like that to his advantage, which we saw over and over in the primary", said Sarah Isgur Flores, the former campaign manager for Republican candidate Carly Fiorina.

For his part, Mr. Trump on Thursday headed back to Cleveland, site of his July presidential convention, to proclaim himself the "biggest cheerleader" for the school choice movement.

Manganiello to antagonize Affleck's Batman as Deathstroke
He also confirmed that Deathstroke will be the main antagonist in the still-untitled Batman movie. He said on his Tumblr page, "The character of Slade Wilson is now tied up in another DC project".

As he often does, Trump took to Twitter in response: "Hillary just gave a disastrous news conference on the tarmac to make up for poor performance last night".

"Any time anyone states says that generals are rubbish or an individual is not a hero because he or she was captured I find it appalling", Cooke said in a statement, referring to Trump saying Sen.

A day earlier, he provided a new wealth of detail on his plans for the military, describing massive boosts in troops and equipment, and vowing he'd do away with congressional budget caps he said have hollowed out the Pentagon and made it tougher to face worldwide threats. "The Iraq War began in March 2003, more than a year before this story ran, thus nullifying Trump's timeline". That lead remains in a four-way race with Clinton at 44 percent support, Trump at 39 percent.

Trump's outlandish comments and bombastic bravado have gotten him into hot water with moderate voters.

The Suffolk University poll was conducted September 5-7 using phone interviews with 500 likely North Carolina voters.

"Libertarian Gary Johnson could decide the presidential election in the Buckeye State", said Peter A. Brown, the Connecticut-based poll's assistant director.

"As a woman who served our nation, know that Donald Trump can't be trusted to properly handle military service members, as well as victims of sexual assault and trauma", she added.