LOS ANGELES -- Donald Trump, who has struggled with foreign policy questions in the run-up to the second Republican presidential debate, is slated to address national security challenges at an address here Tuesday.

Just a day before he once again faces off with his GOP presidential rivals, the Republican front-runner will speak at a fundraiser for the conservative 501 (c) 4 nonprofit Veterans for a Strong America aboard the USS Iowa, which is now a museum. The group said the presidential candidate plans to speak about issues important to members of the military, such as international challenges and veteran's issues.

At Wednesday's debate, Trump is expected to face tough questions about his foreign policy knowledge. Last week, his failure to answer tough security and international affairs queries posed by radio host Hugh Hewitt -- who will be challenging candidates at this week's debate -- highlighted his lack of foreign policy bona fides.

Unable to answer detailed questions about terrorist leaders, Trump said the questions themselves were flawed.

What Donald Trump is doing on the campaign trail

U.S. Republican presidential nominee Donald Trump speaks at a campaign event at Trump Doral golf course in Miami, Florida, U.S. July 27, 2016. REUTERS/Carlo Allegri (Carlo Allegri/Reuters)

"Well, that is a gotcha question, though," he responded to Hewitt. "I mean, you know, when you’re asking me about who’s running this, this this, that’s not, that is not, I will be so good at the military, your head will spin."

Trump also sidestepped attempts to pressure him to lay out his military strategy, saying that "you don’t want to let people know what you’re going to do with respect to certain things that happen." In the past, he has called for more resources to be directed to the military.

Another issue where Trump has hit turbulence on his ascent to the top of the polls will also take center stage at Tuesday's event.

Trump, who did not serve in the military, faced criticism earlier this summer for appearing to speak dismissively about both the military record and the veterans issues record of Sen. John McCain (R-Ariz.), a naval aviator who was a prisoner of war during the Vietnam War.

VSA chairman Joel Arends defended Trump during that controversy, though he did not embrace the businessman's assessment of McCain's record.

Trump himself has said he'd address problems with the VA health care system by "firing everyone at the VA" and that the problems facing the system could be addressed by "getting Trump elected president."

Nearly 3,000 people in San Pedro, the Los Angeles community where the battleship is moored, have signed a petition calling for Trump's event to be moved, according to local reports, and some activists have announced plans to protest his appearance.