Romney noted that he visited Afghanistan and Iraq during his term as Massachusetts governor. But he has limited foreign policy experience.
Still, Romney has been critical of Obama's plans to reduce the military, in addition to the administration's policy toward Syria's handling of the uprising against President Bashar Assad's government.
In a written statement Sunday, Romney said Obama "can no longer ignore calls from congressional leaders in both parties to take more assertive steps in Syria." Romney said the current approach has only given Syrian leaders more time to crackdown on protesters.
World leaders blame the Syrian government for the weekend killing of more than 100 people, including 49 children and 34 women, following peaceful protests.
"I wish I could tell you that the world is a safe place today. It is not," Romney said Monday, ticking off a list of threats including Iran, Pakistan, China, Russia, Venezuela and Mexican drug cartels. He did not mention Syria.
Romney said Monday that America's military might is needed "not so that we just win wars, but so we can prevent wars."
"A strong America is the best deterrent to war that has ever been invented," he said.