CHARLES CITY, Iowa -- At a stop here on his six-day bus trip through Iowa, Sen. Ted Cruz (R-Tex.) told a crowd in a coffee house that when his 5-year-old daughter Catherine tells a lie, "she gets a spanking."

He offered that parenting tip in response to a question about former secretary of state Hillary Clinton's role in the aftermath of the September 2012 attack on a U.S. compound in Benghazi, Libya, in which four Americans, including U.S. Ambassador J. Christopher Stevens, were killed. Republicans have accused Clinton, the Democratic presidential front-runner, of having purposely misled the public as to the cause of the incident.

A woman in the audience had asked: "For three and a half years people in Washington have been skirting around Benghazi and no one has been held accountable. I want to know what you would do. Someone needs to pay."

Republican presidential candidate Ted Cruz mocks Democratic front-runner Hillary Clinton at a town hall in Iowa. (Reuters)

"Ma'am you are exactly right. What happened in Benghazi is a national disgrace. Four Americans were murdered. We lost the first ambassador in the line of duty since the Carter administration," Cruz said. "The immediate response of Barack Obama and Hillary Clinton and the entire administration was to engage in deception, obstruction and cover up. They began by falsely blaming it on some ridiculous internet video, but even before that was the question that everyone should ask is why was security not there in the first place when the ambassador said over and over again, keep us safe."

Cruz  added: "We do know Hillary told her daughter Chelsea, well gosh, I knew it was a terrorist attack, while we were out telling the American people it wasn't. You know I'll tell you, in my house, if my daughter Catherine, the five-year-old, says something she knows to be false, she gets a spanking."

"Well, in America, the voters have a way of administering a spanking," Cruz said.

Earlier in the bus trip, Cruz had talked about how he missed his daughter and the "marshmallow hugs" that she gives him.

Cruz has narrowly led Donald Trump in a string of recent polls here, claiming the top spot with a little more than three weeks to go until the Iowa caucuses on Feb. 1.