Republican frontrunner for the 2016 presidential campaign Donald Trump vowed to pursue an "America first" foreign policy in a speech delivered here.
"My foreign policy will always put the interests of the American people and American security above all else," Trump said on Wednesday, Xinhua news agency reported.
"America first will be the major and overriding theme of my administration."
Trump criticised President Barack Obama and Hillary Clinton for their foreign policies, saying that they both had different roles in helping the Islamic State (IS) group grow.
"If President Obama's goal was to weaken America, he could not have done a better job," Trump said.
He added that if he is elected, the IS will be gone "very, very quickly," and "their days are numbered."
In the speech, the real estate mogul also lamented the deterioration of America's military and blamed Obama for shrinking the defense budget.
"We will spend what we need to rebuild our military," Trump said. "Our military dominance must be unquestioned by anybody and everybody."
Trump said that he would be open to using American force when necessary.
"I will not hesitate to deploy military force when there is no alternative. But if America fights, it must only fight to win," he said. "I will never send our finest into battle unless necessary, and I mean absolutely necessary, and will only do so if we have a plan for victory with a capital V."
Trump's speech came after he clinched major victories on Tuesday as he swept all five primary states -- Pennsylvania, Maryland, Connecticut, Delaware and Rhode Island -- and took a strong majority of the 118 delegates at stake.
The wins decreased the odds for a contested convention this summer in Cleveland, a scenario his rivals had banked on to stop him from securing the Republican nomination.
"This to me was our biggest night," Trump said in his victory speech. "I consider myself the presumptive nominee."