Former Florida Gov. Jeb Bush speaks during a town hall meeting, May 16, 2015, at Loras College in Dubuque, Iowa.
Former Florida Gov. Jeb Bush speaks during a town hall meeting, May 16, 2015, at Loras College in Dubuque, Iowa.

Eleven U.S. Republican presidential contenders gathered in the central state of Iowa on Saturday to appeal to party activists on why they should get the party's 2016 presidential nomination.

The forum was sponsored by the Iowa Republican Party and was dominated by discussions of Iran, Islam and the unrest in the Middle East, with several candidates calling for a  tougher stance against Tehran and more attacks on Islamic State insurgents.

The prospective candidates called for a stronger American presence in the world but differed on just how tough the U.S. should be on its enemies.

Republican presidential candidate, former Pennsylv
FILE - Republican presidential candidate, former Pennsylvania Sen. Rick Santorum gives a thumbs up during his election night party, March 13, 2012, in Lafayette, La.

Former Senator Rick Santorum's answer for handling Iran was to "load up our bombers and bomb them back to the seventh century." But Kentucky Senator Rand Paul, a libertarian Republican, questioned whether the 2003 invasion of Iraq was worth it, considering the more recent rise of the Islamic State.

Other Republicans blamed the rise of the Islamic State on Democratic President Barack Obama for not leaving a post-war force in Iraq after the U.S. troop withdrawal at the end of 2011.  Several of the prospective candidates accused Mr. Obama of not taking the threat of Islamic militants seriously.

One leading Republican contender, former Florida Governor Jeb Bush, is viewed by many Republicans as a political moderate compared to others seeking the party's presidential nomination. But he assured the Iowa activists that he governed his state as a conservative.

"There's a difference between the liberal, progressive agenda and a conservative agenda applied the right way," Bush said.   

GOP 2016 Paul
FILE - Sen. Rand Paul of Kentucky speaks in Milford, N.H., April 8, 2015.

The prospective candidates also called for lower taxes, tougher immigration policies, less federal involvement in education, all issues important to Republican voters.  They also took jabs at the leading Democratic presidential candidate, former Secretary of State Hillary Clinton, with most criticizing her for not answering more questions from voters and news reporters during her campaign events.

Iowa holds the first nominating contest for the 2016 U.S. presidential election early next year.