US President Barack Obama has called the debate surrounding "radical Islam" a political distraction, stressing that calls for tougher talk on terrorism and a strict ban on Muslim immigration would make Muslim Americans feel betrayed by their government.

Obama told reporters after meeting with the US National Security Council on Tuesday that the Orlando shooting that left 49 people dead, or any attack organised by groups such as the Islamic State of Iraq and the Levant group (ISIL, also known as ISIS), was not possible to prevent by using the label.

"The killer was an angry, disturbed, unstable, young man who became radicalised," he said, adding that Islam had nothing to do with the attack.

"What exactly would using that label accomplish? What exactly would it change? Would it make ISIL less committed to trying to kill Americans? Would it bring in more allies? ... The answer is: none of the above," he said.

"Calling a threat by a different name does not make it go away. This is a political distraction."

He said US intelligence and military staff know well who the enemy is and they work countless hours to protect "all Americans including politicians who tweet and appear on cable news shows".

War against ISIL

Obama said the idea that the administration is confused about the enemy "would come as a surprise to the thousands of terrorists who we've taken off the battlefield".

While parrying his political foes, Obama also sought to show Americans that the war against the ISIL in Syria, Iraq and Libya, while slow, was being won.

He said the number of foreign fighters joining the armed groups was plummeting.

"ISIL lost nearly half of the populated territory it had in Iraq and it will lose more. ISIL continues to lose ground in Syria as well," Obama said.

"In short, our coalition continues to be on offence. ISIL is on defence."

Obama's remarks were his first reaction to Donald Trump's speech on Monday after Sunday's mass shooting, and perhaps his strongest yet on the threat he sees the Republican candidate poses to the US politics and security.

Obama said Trump's plan to bar foreign Muslims from entering the US ignored America's history of targeting ethnic and religious groups amid period of anxiety and would undermine American values.

"If we ever abandon those values, we would not only make it a lot easier to radicalise people here and around the world, but we would have betrayed the very things we are trying to protect." Obama said. "And then the terrorists would have won and we cannot let that happen. I will not let that happen."

Obama said that treating Muslim-Americans differently would not make the US safer.

"Are we going to start treating all Muslim Americans differently? Are we going to start subjecting them to special surveillance? are we going to start discriminating them because of their faith?"

"We're starting to see where this kind of rhetoric and loose talk and sloppiness about who exactly we're fighting, where this can lead us."

The US president said it would make the country less safe by fuelling the notion among followers of ISIL that the West hates Muslims.

"They want us to validate them by implying that they speak for those billion-plus people, that they speak for Islam. That's their propaganda, that's how they recruit," he said.

"And if we fall into the trap of painting all Muslims with a broad brush and imply that we are at war with an entire religion, then we are doing the terrorists work for them."