U.S. President Barack Obama vowed to continue airstrikes against the Islamic State of Iraq and Syria (ISIS) targets and said he would "not hesitate to take action" against the militants in Syria.

"I will not hesitate to take action against [ISIS] in Syria, as well as Iraq," he said during a live televised nationwide address Wednesday updating Americans on what he promised would be a "comprehensive and sustained" strategy against the militants.

He referred to a "core principal" of his presidency: "If you threaten America, you will find no safe haven."

The U.S. has already conducted more than 150 airstrikes against ISIS targets since early August. Obama said the campaign has been necessary to protect American lives and interests.

More support for local forces

In addition to airstrikes, Obama outlined three more steps to the ongoing effort: increased support to ground troops, using counter-terrorism capabilities to prevent ISIS attacks, and providing humanitarian assistance.

ISIS Barack Obama

U.S. President Barack Obama delivered a live televised address to the nation on his plans for military action against ISIS, saying he would 'not hesitate to take action' against the militants in Syria. (Saul Loeb/Reuters)

“America will lead a broad coalition to roll back this terrorist threat,” he said in his address Wednesday night. “Our objective is clear: we will degrade, and ultimately destroy ISIL through a comprehensive and sustained counter-terrorism strategy.”

Obama pledged more support to local forces fighting against ISIS.

America will deploy 475 more service members to Iraq. These troops will not be involved in a combat mission, he said. Instead, they will focus on supporting Iraqi and Kurdish forces with training, intelligence and equipment. After this deployment, America will have sent more than 1,500 troops to Iraq this summer.

In June, Obama sent several hundred troops to Iraq. They assessed how the U.S. could best support local forces.

The U.S. has also increased its military assistance to the Syrian opposition.

America will continue to work with its partners to stop foreign fighters from entering and exiting the Middle East, he said.

Canada 'united with our allies'

Obama emphasized that this campaign, which was decided upon after consultations with allies and Congress “will be different from the wars in Iraq and Afghanistan.”

No U.S. combat troops will fight on foreign soil. The U.S. will only engage its air power to support partner forces on the ground.

He said his campaign against ISIS will be modelled after American counter-terrorism campaigns in Yemen and Somalia.

Obama faced criticism in August when he said he did not yet have a strategy for combating ISIS despite having already launched airstrikes in the region.

The Canadian government responded to Obama's comments shortly after he delivered his address.

Canada is "united with our allies in recognizing the need to address this barbaric terrorist threat," wrote Prime Minister Stephen Harper's spokesman Jason MacDonald in a statement.

This is why Canada has provided humanitarian aid, delivered military aid to Iraqi forces and deployed Canadian Armed Forces members to assist Iraqi forces, the statement read. Canada's troops are on a 30-day, non-combat mission.

"We have no plans to deploy any military assets in Syria," he wrote.

With files from The Associated Press