Gaffe-prone Vice President Joe Biden offended many Twitter users while describing Sept. 11 as "bittersweet" during a ceremony Tuesday for those who lost their lives on United Flight 93, which crashed in a Pennsylvania field.

"And its an honor, a genuine honor to be back here today but like all of the families, we wish we weren't here. We wish we didn't have to be here. We wish we didn't have to commemorate any of this." Biden said. "It is a bittersweet moment for the entire nation, for all of the country, particularly for those family members gathered here today."

Some questioned the use of "bittersweet" during the somber ceremony in Shanksville, Pa., but as Charlie Sperling of the conservative Washington Examiner noted, Biden was speaking at the site where United Flight 93 crashed. The heroic efforts of the plane's passengers prevented the aircraft from hitting the U.S.  Capitol building, believed to be the terrorists' target.

"If you are commemorating Flight 93; that specific event is one of both heroism and tragedy," Sperling noted.

Biden also shared his personal loss during the ceremony, when he described losing his first wife and daughter in a car accident. He told families of the victims of Flight 93 that he hoped their pain would east with time. While there hasn't been official word from Biden's office on what he meant when he said, "bittersweet," this could have also been what Biden was alluding to by using that phrase.

Conservative pundit Michelle Malkin, who usually doesn't miss a chance to bash the administration, held back on criticism.

"Lots of stupid going around today, but I'm not jumping on Biden for his 'bittersweet' remark," Malkin tweeted, adding a link to a Politico story on Biden's speech. "Full context==>"

But other Biden bashers on Twitter didn't hold back.

"Hey Biden, there's nothing 'bittersweet' about today you ignorant moron," said @olliblog.

"9/11 is 'bittersweet'? Biden is a dope," said @Twin66.

"That idiot Joe Biden did it again. 'Today is a bittersweet.' What part is sweet about today?" wrote Jason Fry.

"Just when you thought there were hardly words to describe 9/11's significance, our illustrious Veep Joe Biden: 'It is a bittersweet moment,'" said Jess Fields.

"In speech to #9-11 families, #Biden says today 'bittersweet' moment for America. Someone needs to get that man a dictionary. #alwaysremember," wrote Terri Mallioux.