US President Barack Obama speaks at the White House Summit on Countering Violent Extremism in Washington, February 18, 2015. [Photo/Agencies]

WASHINGTON - Though US President Barack Obama's keynote speech on Wednesday at the White House Summit on Countering Violent Extremism lasted for half an hour, to sum up his key points breaks no sweat.

While Obama emphasized the urgency to stay vigilant against those who start getting radicalized, the bulk of his speech was dedicated to speaking the Muslims around the world out of the notion that he was leading a war against them.

"We are not at war with Islam. We are at war with people who have perverted Islam," said Obama.

"Leading up to this summit, there's been a fair amount of debate in the press and among pundits about the words we use to describe and frame this challenge," said Obama in response to the criticism from his Republican political foes that his avoidance of terms such as "Islamic extremism" after recent attacks either conducted or inspired by the extremist group Islamic State (IS) showed his negligence of the significance of the threat.

Obama said the reason for not using the term "Islamic extremism" was to deny terrorist groups any religious legitimacy.

"I want to be very clear about how I see it. Al-Qaida and ISIL and groups like it are desperate for legitimacy. They try to portray themselves as religious leaders, holy warriors in defense of Islam," said Obama.

"We must never accept the premise that they put forward, because it is a lie, nor should we grant these terrorists the religious legitimacy that they seek. They are not religious leaders; they're terrorists," said the US president. White House spokesman Josh Earnest said earlier on Wednesday that though the White House acknowledged that a particularly virulent strain of extremist ideology has tried to insert itself in the Muslim community, other forms of extremism have also prompted others to carry out acts of violence.

"Extremism has taken a variety of forms in this country in a way that has had violent results," Earnest said.

Earnest's remarks were echoed by Obama, who proclaimed that no religion was responsible for terrorism, a reference greeted with thunderous applause.

As he spoke publicly to reject equating Islam with terrorism, Obama said Muslim leaders in return need to do more than discredit the notion that Western nations are determined to suppress Islam.

"We've got to be much more clear about how we're rejecting certain ideas," said Obama, warning that such ideas made individuals, especially young people who already may be disaffected or alienated, more ripe for radicalization.

During the half-hour speech, the president also noted other challenges in countering violent extremism, including the economic and political grievances that terrorists exploited, adding that community also plays an important role in the fight against violent extremism.