No third-party presidential candidates will participate at next week's forum dedicated to veterans issues.
NBC's Matt Lauer will host what's being billed as the first-ever "Commander-in-Chief Forum" 8 p.m. Wednesday in New York City at the Intrepid Sea, Air & Space Museum, site of the decommissioned aircraft carrier USS Intrepid.
The hour-long event, organized by the veterans organization Iraq and Afghanistan Veterans of America, will air on the NBC and MSNBC cable channels and live-stream on IAVA's Facebook page.
During the event, Republican presidential nominee Donald Trump and his Democratic opponent Hillary Clinton will make separate appearances to field questions from Lauer and veterans rather than debate issues together on stage.
Third-party candidates Gary Johnson, a former Republican governor of New Mexico running on the Libertarian ticket, and Jill Stein, a physician backed by the Green Party, won't participate in the forum but may do so at a future event, according to IAVA.
"We are a non-partisan organization and IAVA members are extremely diverse," Paul Rieckhoff, founder and chief executive officer of the organization, said in a statement on Friday after speaking to Johnson the day before.
"IAVA has always been committed to the most robust public conversation around veterans issues and we are eager to engage Gov. Johnson and all candidates further in the days to come," he added.
The group has said it extended a formal invitation to Johnson to participate in a separate event and also reached out to Stein. A spokeswoman didn't immediately return an email and call requesting comment on Friday evening, nor did a spokesperson Stein campaign.
Joe Hunter, a spokesman for Johnson, confirmed the Libertarian candidate was not invited to participate in next week's IAVA event. "He has, however, spoken with IAVA CEO and Founder Paul Rieckhoff, and we are exploring possibilities with IAVA for a future event," Hunter said in an email.
Clinton and Trump carry sizeable leads over the third-party candidates in national polls of likely voters.
A recent poll by USA Today and Suffolk University of a four-way presidential ballot showed Clinton leading with 42 percent of the vote, followed by Trump with 35 percent, Johnson with 9 percent, Stein with 4 percent. About 10 percent of respondents were undecided.
The poll of 1,000 likely voters was conducted Aug. 24 through Aug. 29 and has a margin of error of plus or minus 3 percentage points.
Even so, the majority of likely voters want to see third-party candidates on the debate stage, even if they don't hit the 15-percent threshold to do so, according to David Paleologos, director of the Suffolk University Political Research Center in Boston, who helped conduct the poll.
Johnson has reportedly received slightly higher support from U.S. military members -- 13 percent of almost 2,000 active-duty, Guards and reserve respondents in a Military Times survey conducted in July. And some veterans have reacted strongly to his exclusion in the upcoming IAVA forum.