LAS VEGAS, NV – Waiting in line for between six to eight hours, Las Vegas residents and visitors are out in force donating blood for victims of the deadliest mass shooting in modern US history.

Resident Shanda Maloney said she had seen the news about what was happening Sunday night. Sirens were wailing in the distance as ambulances rushed to nearby University Medical Center, less than a mile from her house, she said.

“Hearing all the sirens around, you feel completely helpless,” she said. “I just started tweeting if you need a ride (I’ll come pick you up).”

Then Maloney hit the road. “I just started picking people up and giving people rides,” she said. Whether it was to a gas station or home, Maloney said she made sure they got there.

She wasn’t the only one.

Hector Salas and his coworker Glendon Lowder aren’t even from Las Vegas; they’re just in town from Dallas for the NetApp Insight conference.

To them, they’re just doing their part by giving blood today at United Blood Services.

“This is America,” Salas says. “People coming together, helping out.”

Las Vegas Mayor Carolyn Goodman asked residents for blood donations during a news conference following Sunday’s attack at an outdoor Jason Aldean concert. A gunman opening fire from the Mandalay Bay hotel killed dozens and injured hundreds.

“What we ask for is blood — that’s the main thing right now — is that if our people want to do something, and they are healthy, then please donate blood. We’ll have plenty of banks available,” said Goodman.

“I’m in line at United Blood Services on Whitney Ranch right now,” Kelsey Gunther said on Twitter Monday. The “line is about 200 deep.”

Al Mancini was waiting to give blood when he tweeted, “Las Vegas cares.”