Politicians react to Las Vegas massacre, the deadliest mass shooting in modern US history

US and world leaders reacted Monday to the deadly mass shooting at a Las Vegas concert. At least 50 people were killed and mroe than 400 were injured.

By Monday morning, it was already the deadliest mass shooting in modern US history.

A gunman, whom police identified as 64-year-old Stephen Paddock of Nevada, opened fire with what police said were automatic weapons from the 32nd floor of the Mandalay Bay Resort and Casino. Police said he aimed down and across the street at concertgoers who were attending the Route 91 Harvest festival, packed with thousands of people.

Authorities found Paddock dead in his hotel room upon arrival.

Here's what politicians are saying Monday:

 

President Donald Trump:

Republican Sen. Dean Heller of Nevada:

"Nevada families are waking up to the shocking news of the tragic events that occurred last night in Las Vegas. Our communities are all in mourning as we try to understand this senseless massacre on the Strip. I want to thank our first responders for their swift actions and efforts that without a doubt saved numerous lives. I've been in contact with the White House and Governor Sandoval, and I will continue to monitor the situation as this horrific event unfolds. Lynne and I are praying for all of the victims and their families who are experiencing immense pain and grave, shocking loss that cannot be measured."

Republican Gov. Greg Abbott of Texas:

"The news of this senseless act of violence in Las Vegas overnight is heartbreaking. Cecelia and I are beyond saddened by the tremendous loss of life. Texas mourns and prays for the victims of this tragedy, and the entire Las Vegas Community, in this time of unimaginable pain."

Democratic National Committee Chair Tom Perez:

"This morning, America woke to news of the worst mass shooting in our history. Our hearts are with the people of Las Vegas and all those affected by this despicable act of terror. In the coming days, we will surely learn of the heroism of ordinary Americans and selfless first responders who risked their lives to save others. We will be reminded that the courage of the American people will always outlast the cruelty of cowards. As Americans, we cannot give in to fear or hatred. We must be united against all those who perpetrate such terror, and do everything we can to ensure that vicious attacks like this become a thing of the past."

Democratic Sen. Richard Blumenthal of Connecticut:

"Although many details of this mass shooting remain unclear, one thing is certain: yet again, we are watching in horror as another American community is torn apart by the terrible devastation wrought by a gunman. My heart breaks for Las Vegas: the victims, their families, their friends, and their entire community. It has been barely a year since what was previously the largest mass shooting in American history - the deadly attack at Pulse nightclub. In the interim, thousands more have been lost to the daily, ruthless toll of gun violence. Still, Congress refuses to act. I am more than frustrated, I am furious."

Democratic Sen. Chris Murphy of Connecticut:

"My heart goes out to the victims, their families, the first responders, and the entire Las Vegas community. Nowhere but America do horrific large-scale mass shootings happen with this degree of regularity. Last night's massacre may go down as the deadliest in our nation's history, but already this year there have been more mass shootings than days in the year. "This must stop. It is positively infuriating that my colleagues in Congress are so afraid of the gun industry that they pretend there aren't public policy responses to this epidemic. There are, and the thoughts and prayers of politicians are cruelly hollow if they are paired with continued legislative indifference. It's time for Congress to get off its ass and do something."

2016 Democratic presidential nominee Hillary Clinton:

Democratic Sen. Elizabeth Warren of Massachusetts:

Democratic Sen. Tim Kaine of Virginia:

Democratic Sen. Cory Booker of New Jersey:

Former President Bill Clinton:

Canadian Prime Minister Justin Trudeau:

Republican Gov. Brian Sandoval of Nevada:

Senate Minority Leader Chuck Schumer:

Former President Barack Obama:

Democratic Sen. Kirsten Gillibrand of New York:

First lady Melania Trump:

Republican Sen. Rand Paul of Kentucky:

Democratic Sen. Al Franken of Minnesota:

Democratic Sen. Bob Casey of Pennsylvania:

Democratic Sen. Catherine Cortez Masto of Nevada:

White House press secretary Sarah Huckabee Sanders:

Democratic Sen. Kamala Harris of California:

Republican Gov. John Kasich of Ohio:

Republican Sen. Marco Rubio of Florida:

Vice President Mike Pence:

Australian Prime Minister Malcolm Turnbull:

2012 Republican presidential nominee Mitt Romney:

White House counselor Kellyanne Conway:

Former Democratic Rep. Gabrielle Giffords of Arizona:

Mexican President Enrique Peña Nieto: