Lawmakers, military leaders set to join President Obama at Fort Hood memorial

President Barack ObamaBarack ObamaWATCH LIVE: Obama speaks at African American Museum opening Obama talks racial tension at African-American museum opening Trump in 2011: Clintons ‘have done so much’ for blacks MORE, military leaders and a host of lawmakers are expected to attend Tuesday’s memorial service for the 13 victims slain in last week’s shooting rampage at an Army base.

The Army has offered to fly lawmakers to the service; as of press time, at least 15 Senate and House members had expressed interest. The passenger plane taking off from Andrews Air Force Base, Md., on Tuesday morning can fit 30 people.

First lady Michelle ObamaMichelle ObamaTrump: We are proud of African-American history museum George W. Bush and Michelle Obama share hug on stage Michelle Obama, Biden, Bill Clinton to hit post-debate campaign trail MORE will be attending the service with her husband, who will deliver a speech. Defense Secretary Robert Gates, Chairman of the Joint Chiefs of Staff Adm. Mike Mullen, Army Chief of Staff Gen. George Casey and Army Secretary John McHugh also are expected to be present for the service, scheduled for 1 p.m. Central Standard Time.

The service will include a roll call of the names of those killed and a 21-gun salute. White House press secretary Robert Gibbs said the Obamas will meet with victims’ families and the president will speak at the memorial to “a community obviously saddened and stricken by the events of last week.”

It is unclear how many lawmakers will attend the event, though sources said senators who had expressed interest in traveling through the military’s accommodation included Sens. John McCainJohn McCainSenate rivals gear up for debates McCain opponent releases new ad hitting his record Why is the election so close? Experts say it's all in your head MORE (R-Ariz.), Carl LevinCarl LevinThe Fed and a return to banking simplicity What Our presidential candidates can learn from Elmo Zumwalt Will there be a 50-50 Senate next year? MORE (D-Mich.), Richard BurrRichard BurrSenate rivals gear up for debates The Trail 2016: Trump seizes on Charlotte violence Polls: Dem Senate candidates lead in three states MORE (R-N.C.), James InhofeJames InhofeDemocrats blast GOP for ‘sabotaging’ House waterways bill GOP pressures Kerry on Russia's use of Iranian airbase Week ahead: Flint aid fight shifts to House MORE (R-Okla.), John CornynJohn CornynSaudi skeptics gain strength in Congress Why Cruz flipped on Trump Schumer rips 'disappointing' 9/11 bill veto, pledges override MORE (R-Texas), Lamar AlexanderLamar AlexanderOvernight Regulation: Lawsuits pile up against Obama overtime rule The American people are restive, discouraged and sometimes suicidal GOP chairman eyes lame-duck for passing medical cures bill MORE (R-Tenn.), Al FrankenAl FrankenSenators challenge status quo on Saudi arms sales Overnight Defense: Senate rejects effort to block Saudi arms sale | ISIS may have fired chemical agent in Iraq | Trump, Gary Johnson tied among military voters Human rights groups cheer Saudi arms sale vote despite failure MORE (D-Minn.), Amy KlobucharAmy KlobucharOvernight Defense: US attempted hostage rescue in Afghanistan | Defense hawks brace for spending fight | Trump slams 'lies' about Iraq war stance Senators want military separation policy to address trauma-related behavior Senate Dems reignite fight for hearing on SCOTUS nominee MORE (D-Minn.), Kay Bailey Hutchison (R-Texas) and Jack ReedJack ReedOvernight Finance: McConnell offers 'clean' funding bill | Dems pan proposal | Flint aid, internet measure not included | More heat for Wells Fargo | New concerns on investor visas Senate Dems call for investigation into Wells Fargo's wage practices Week ahead: Negotiators near deal on defense bill MORE (D-R.I.).

Some senators may also make the trip on their own, including Sens. Kent Conrad (D-N.D.), Russ Feingold (D-Wis.), Herb Kohl (D-Wis.) and Mark UdallMark UdallColorado GOP Senate race to unseat Dem incumbent is wide open Energy issues roil race for Senate Unable to ban Internet gambling, lawmakers try for moratorium MORE (D-Colo.), according to a source familiar with the planning for the event.

The Senate is in session Tuesday and is considering the 2010 Military Construction and Veterans Affairs appropriations bill.

Majority Leader Harry ReidHarry ReidBlack Caucus demands Flint funding from GOP Report: Intelligence officials probing Trump adviser's ties to Russia White House preps agencies for possible shutdown MORE (D-Nev.) said early Monday evening that he hoped to hold votes on the bill on Tuesday, but indicated a number of senators would be in Texas for the Fort Hood service.

Reid will ask for a moment of silence when the Senate convenes on Tuesday .

The House is not in session this week and it is unclear how many lawmakers from that chamber will attend the event. Those expressing interest included Reps. Tom PetriTom PetriDem bill would make student loan payments contingent on income Black box to combat medical malpractice Two lawmakers faulted, two cleared in House Ethics probes MORE (R-Wis.), Sheila Jackson LeeSheila Jackson-LeeDems hijack IRS hearing to ask about Trump’s taxes The Hill's 12:30 Report Why a new 'app' would be essential to public education in the fight against Zika MORE (D-Texas), Kay GrangerKay GrangerGOP divided over 0M for climate fund GOP votes down funding for global climate fund Overnight Healthcare: Momentum on mental health? | Zika bills head to conference | Only 10 ObamaCare co-ops left MORE (R-Texas), John Carter (R-Texas), Sam JohnsonSam JohnsonRepublican Study Committee elders back Harris for chairman IRS publishes guidelines on tax relief for wrongfully incarcerated people Overnight Finance: House votes to rein in IRS; Ryan won't set Puerto Rico timeline MORE (R-Texas) and Betty McCollum (D-Minn.).

Maj. Nidal Malik Hasan, the Army psychiatrist accused of shooting to death 12 soldiers and a civilian at Fort Hood and injuring at least 30 others, is conscious and able to talk, according to several media reports on Monday. Authorities say he fired more than 100 rounds Thursday at a soldier-processing center before being shot by civilian police.

Senate Homeland Security Committee Chairman Joe Lieberman (I-Conn.) and ranking member Susan CollinsSusan CollinsSwing-state Republicans play up efforts for gun control laws Reid knocks GOP on gun 'terror loophole' after attacks GOP pressures Kerry on Russia's use of Iranian airbase MORE (R-Maine) formally announced on Monday that their panel will be conducting an investigation into the shooting beginning with a public hearing next week.

“This murderous attack should be examined from every angle to make sure nothing like this occurs again,” Lieberman said. “While we in no way will interfere with the Army’s or FBI’s criminal investigations, the committee will be conducting an investigation into what Maj. Nidal Malik Hasan’s motives were, whether the government missed warning signs that should have led to expulsion and what lessons we can learn to prevent such future attacks.”

Premature speculation about the causes of the Fort Hood shooting could cause a backlash against Muslim soldiers, Casey, the Army chief of staff, said on several Sunday morning shows. Casey said no one should rush to judgment about the shooter’s reported anti-American views.

“The speculation could potentially heighten the backlash against some of our Muslim soldiers,” he told ABC’s “This Week.”

As horrific as the shooting was, “it would be an even greater tragedy if our diversity became a casualty here,” he warned.

Casey said investigators believe Hasan was the only shooter involved.

Sam Youngman contributed to this report.