Republican presidential nominee Donald Trump has said he will expand all areas of the US military if he wins November's election.
Mr Trump called for more troops, more planes and more boats at a rally in Philadelphia.
He also wants US generals to come up with a plan to defeat the self-styled Islamic State (IS) in his first 30 days in the White House.
Recent polls show the race for the presidency has narrowed.
Democrats and even some Republicans have painted Mr Trump as unfit to serve as US commander-in-chief but he has made up some ground on rival Hillary Clinton.
In his speech he called his vision for the US military "peace through strength".
"I am proposing a new foreign policy focused on advancing America's core national interests, promoting regional stability, and producing an easing of tensions in the world. This will require rethinking the failed policies," he said.
"Our adversaries are chomping at the bit," he added.
Mr Trump said his plan would be paid for by cutting government waste, collecting uncollected taxes and slimming down the federal workforce.
He also called for US Nato allies to meet their obligations to spend 2% of national income on defence.
Earlier this week, Mr Trump was endorsed by 88 former military leaders in an open letter, who declared the Republican nominee "has the temperament to be commander-in-chief".
Clinton 'trigger-happy'
Both Mr Trump and Mrs Clinton will take part back-to-back in a national security forum on Wednesday.
The forum, to be hosted by the Iraq and Afghanistan Veterans of America, will include questions from an audience of military service members.
During his speech Mr Trump attacked Mrs Clinton as "trigger-happy and very unstable".
But on Tuesday Mrs Clinton said US voters "know they can count on me to be the kind of commander-in-chief who will protect our country and our troops, and they know they cannot count on Donald Trump".
She added: "They view him as a danger and a risk.''
Despite making support for the military a signature issue in his campaign, Mr Trump has at various times drawn criticism from military members.
Most notably, he was involved in a recent spat with family members of a Muslim-American soldier killed during the Iraq War.
Some veterans and families of military members killed in action protested outside Trump Tower in New York on Wednesday.