More than 100 people were killed in a series of terrorist attacks in Paris on Friday (Nov. 13), and country stars have been sharing their thoughts and prayers for the city and the victims on social media.

CNN reports that at least six shootings took place in Paris -- including at an Eagles of Death Metal concert -- and three explosions occurred at the Stade de France in Saint-Denis. Attackers reportedly used AK-47s.

"This is an attack not just on Paris, not just on the people on France, but an attack on all humanity and the universal values we share," says U.S. President Barack Obama, calling the attacks "[an] outrageous attempt to terrorize innocent civilians."

French President Francois Hollande has declared a state of emergency; the country's borders are closed, and Paris police are instructing people to stay home. French authorities have launched an investigation, but as of 7PM ET on Friday, no terrorist group has claimed responsibility.

"We have to show compassion and solidarity and we also have to show unity and keep our cool," says President Hollande. "France must be strong and great."

Click through the photo gallery above to see tweets from Brad Paisley, Cassadee Pope, the Bellamy Brothers and more. The Boot extends our thoughts and prayers to the people of Paris during this tragedy.