PHILADELPHIA — Republican Donald Trump vowed Wednesday to boost defense spending and deploy more active troops, fighter planes, Navy ships and submarines as he works to convince skeptics in both parties that he’s ready to lead the world’s most powerful military.

The New York businessman, who has struggled at times to demonstrate a command of foreign policy, also seemed to acknowledge he does not currently have a plan to address cybersecurity or the Islamic State group.

If elected, Trump said he would give military leaders 30 days to formulate a plan to defeat the group that is also known as ISIS or ISIL. He also said he would ask the joint chiefs of staff to conduct a review of the nation’s cyber defenses to determine all vulnerabilities.

Trump’s address came hours before his national security acumen is tested at a “commander in chief” forum on NBC.

“We want to deter, avoid and prevent conflict through our unquestioned military strength,” Trump declared of his Democratic opponent in his Wednesday speech, delivered inside the exclusive Union League of Philadelphia, which first allowed women in 1986.

The appearances mark an intense, two-day focus on national security by Trump, who has offered tough rhetoric – but few details – on America’s challenges abroad.

Trump’s rival, Democrat Hillary Clinton, has tried to paint the billionaire businessman as erratic, making the case that his disposition would be a major liability on the world stage.

“They 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,” Clinton said Tuesday. “They view him as a danger and a risk.”

Trump’s team has worked aggressively in recent days to turn deflect such criticism back at Clinton.

“She’s trigger-happy and very unstable,” Trump said of his Democratic opponent, calling her use of a private email server while secretary of state “reckless.”

Clinton and Trump appeared at separate times during Wednesday night’s forum.