Published: May 12, 2013 5:38 PM EDT

WASHINGTON (AP) - Former ambassador Thomas Pickering says he was willing to testify last week to a House panel looking into the attack on the U.S. diplomatic post in Benghazi, Libya last year -- but that he was blocked from doing so.
 
Pickering, on NBC's "Meet the Press" today, took issue with a claim from the committee chairman, Republican Darrell Issa (EYE'-suh), who said Pickering "refused to come before our committee."
 
Sitting next to Issa, Pickering responded, "That is not true." He said in a separate interview that he had asked, through the White House, to appear -- and that he could have answered many of the questions lawmakers raised. Those questions included whether U.S. military forces could have saved Americans if they had dispatched F-16 fighter jets to the consulate.
 
Pickering and former Joint Chiefs chairman Mike Mullen produced a report critical of security in Benghazi, but Pickering says then-Secretary of State Hillary Rodham Clinton wasn't to blame.
 
Meanwhile, there's still a focus on the talking points used by U.N. Ambassador Susan Rice in the days after the attack, when she said it stemmed from a protest over an anti-Islamic video. A series of emails between the State Department and the CIA led to the erroneous description. And Republican Sen. John McCain tells ABC it was a "cover-up." He's again calling for a select committee to investigate.