Donald Trump defended his tight-lipped anti-terror strategy on Monday, claiming the American public, along with enemies of the U.S., do not need to know the details of his planned military campaign against the Islamic State.

"I just want to say that we are going to hit ISIS, but I want to say this: the American public doesn't need to know the date, time [and] second that we're going to attack, that we're going to attack from the eastern quadrant," Trump told a group of veterans at a town hall in Herndon, Va., hosted by the Retired American Warriors PAC.

"They just want to see victory," he added.

The Republican presidential nominee has long criticized the Obama administration and Hillary Clinton for divulging their separate strategies on defeating radical Islamic militants in the Middle East. Eliminating the "element of surprise" gives such groups an immediate advantage, Trump said.

"I don't pretend to be a general or admiral or anything else, but every time I see President Obama get up and say 'Ladies and gentleman, we're sending 50 people to Iraq' – number one, that's such a low number the enemy is saying, 'Is that all?'" Trump said, drawing laughter from the crowd. "And number two, that puts a target on their back."

Speaking directly to a retired general who had initially asked him about his anti-terror strategy, Trump then added: "Are we allowed to have, in the military anymore … an element of surprise?

"It's called an ancient strength and we don't use it anymore," he said.