After the deadliest mass shooting in modern U.S. history left at least 58 people dead, plus the gunman, and more than 500 injured at a music festival in Las Vegas late Sunday night, lawmakers responded by offering thoughts and prayers to the victims and their families.

President Donald Trump tweeted Monday morning to offer his “warmest condolences and sympathies.”

My warmest condolences and sympathies to the victims and families of the terrible Las Vegas shooting. God bless you! — Donald J. Trump (@realDonaldTrump) October 2, 2017

Soon after, Vice President Mike Pence tweeted similar sentiments.

To victims, families & loved ones affected by this senseless violence in Las Vegas, Karen & I are praying for you & offering our love... — Vice President Pence (@VP) October 2, 2017

...The hearts & prayers of the American people are with you. You have our condolences and sympathies. — Vice President Pence (@VP) October 2, 2017

To the courageous first responders, thank you for your acts of bravery. — Vice President Pence (@VP) October 2, 2017

In a statement to reporters, White House press secretary Sarah Huckabee Sanders affirmed that Trump was being briefed on the situation.

“All of those affected are in our thoughts and prayers,” she said.

Nevada lawmakers, including the governor and U.S. senators, expressed their sympathies and affirmed that they were working with local officials to respond to the violence.

A tragic & heinous act of violence has shaken the #Nevada family. Our prayers are w/ the victims & all affected by this act of cowardice. — Governor Sandoval (@GovSandoval) October 2, 2017

Senseless, horrifying act of violence in Las Vegas tonight. Praying for all the victims & those impacted by the tragedy. — Dean Heller (@SenDeanHeller) October 2, 2017

Spoke with Gov. Sandoval and Attorney General Laxalt and will continue to monitor the situation. — Dean Heller (@SenDeanHeller) October 2, 2017

“My thoughts and prayers are with the families of those killed and wounded in last night’s vicious and senseless attack outside the Mandalay Bay Resort,” Sen. Catherine Cortez Masto (D-Nev.) said in a statement, before thanking first responders and offering support to local officials.

A few lawmakers, mostly Democrats, noted the need for more than just thoughts and prayers. Sen. Kirsten Gillibrand (D-N.Y.) was among them:

This senseless violence must end—thoughts and prayers are simply not enough. We must act to prevent this from happening again. — Kirsten Gillibrand (@SenGillibrand) October 2, 2017

Former Rep. Gabby Giffords (D-Ariz.), who was wounded in a mass shooting in 2011, said that “no person should endure the horror Las Vegas experienced last night.”

Heartbroken by the scene our nation is waking up to this morning. No person should endure the horror Las Vegas experienced last night. — Gabrielle Giffords (@GabbyGiffords) October 2, 2017

Giffords and her husband, Mark Kelly, who have become prominent gun control advocates, held a press conference on Capitol Hill later in the day, imploring Trump and members of Congress to take action.

“What we’re hearing today at the Capitol and the White House are thoughts and prayers. Thoughts and prayers are important. We send our thoughts and prayers, too. But they are not enough,” Kelly said. “Your thoughts and prayers aren’t going to stop the next shooting. Only action and leadership will do that.”

Sen. Bob Casey (D-Pa.) wrote in a series of tweets that “it is not sufficient to just offer thoughts and prayers,” and he criticized his colleagues’ refusal “to take real, meaningful action to curb gun violence.”

Congress must engage in a robust debate about commonsense ways to keep guns, particularly military-style weapons, out of the wrong hands. — Senator Bob Casey (@SenBobCasey) October 2, 2017

And Sen. Chris Murphy (D-Conn.), who became a fierce advocate for gun control following the Sandy Hook massacre in 2012, did not mince words.

“The thoughts and prayers of politicians are cruelly hollow if they are paired with continued legislative indifference,” he said in a statement. “It’s time for Congress to get off its ass and do something.”

Yet Sanders insisted that it was “premature” to discuss policy changes regarding guns and urged people to wait for “all of the facts.”

“There’s a time and place for a political debate, but now is the time to unite as a country,” Sanders said Monday during a White House press briefing, before also offering her “thoughts and prayers.”

See more politicians’ reactions below.

America woke up to heartbreaking news from Las Vegas. We stand united in our shock, our condolences, & our prayers. https://t.co/dKqjJqPIpu pic.twitter.com/B67cklsBkS — Paul Ryan (@SpeakerRyan) October 2, 2017

Keeping #LasVegas in our thoughts this morning after the horrific news. If you're trying to locate missing loved ones, call 1-866-535-5654 — Leader McConnell (@SenateMajLdr) October 2, 2017

Horrified and heartbroken by the awful tragedy in #LasVegas last night. Praying for those lost, wounded & waiting for news from loved ones. — Nancy Pelosi (@NancyPelosi) October 2, 2017

Such a senseless tragedy in Las Vegas. This horrific act has our nation praying for the victims and their families. May God bless us all. — Kevin McCarthy (@GOPLeader) October 2, 2017

Praying for the victims and first responders in Las Vegas and our country right now. This shooting was a horrible and cowardly act. — Senator Rand Paul (@RandPaul) October 2, 2017

Lifting up in prayer all impacted by last night's despicable shooting in Las Vegas & all 1st responders on the scene https://t.co/1Yb9NeHx9w — Ted Cruz (@tedcruz) October 2, 2017

Our hearts are heavy for the victims of the terrible attack in Las Vegas, their families and for all who have been affected. — John Kasich (@JohnKasich) October 2, 2017

I’m praying for all the victims, their families, and our first responders in the #LasVegas #MandalayBay shooting. — Marco Rubio (@marcorubio) October 2, 2017

Our thoughts and prayers are with the victims and their family members affected by the terrible tragedy in #LasVegas. — Mike Enzi (@SenatorEnzi) October 2, 2017

My heart breaks for Las Vegas - prayers to families and loved ones. The nation's conscience must be galvanized. — Richard Blumenthal (@SenBlumenthal) October 2, 2017

MA is praying for the victims, families & 1st responders in #LasVegas. Deeply saddened & horrified to learn of this senseless mass shooting. — Charlie Baker (@MassGovernor) October 2, 2017

Heartbreaking news out of Las Vegas—praying for the victims, their families and our country. — Fla. AG Pam Bondi (@AGPamBondi) October 2, 2017

Thoughts & prayers for #LasVegas victims and their family members. What a heartbreaking, horrific tragedy. #PrayForLasVegas — Louie Gohmert (@replouiegohmert) October 2, 2017

Praying for the victims and their loved ones following the horrific shooting in Las Vegas - and grateful to all the brave first responders. — Sen. Maggie Hassan (@SenatorHassan) October 2, 2017

This article has been updated with additional lawmaker responses.