(CNN) -- A shooting at a house party near Houston left two high school students dead and 19 other people injured, the Harris County sheriff said Sunday afternoon.
The shooting occurred late Saturday night in the Cypress area, the sheriff's office said in a statement.
It started at a birthday party in a two-story home, where more than 100 people were gathered, police said.
Harris County Sheriff Adrian Garcia described it as "a birthday party gone wild."
The shooting was not a result of any "one-on-one confrontation," Garcia said. It began after one partygoer fired a gun into the air "in an apparent celebration of music."
A second person "recklessly reacted to the gunfire and shoots into the crowd."
Most of the 19 injured suffered gunshot wounds. One person suffered a broken leg trying to flee from the gunfire, Garcia said.
"Any time you promote a birthday party on social media, you have no control over who to expect at your door," Garcia said. "Any time that you have to factor in the possibility of a bouncer and being searched at the door, you've already taken a turn for the worst."
Police are searching for two shooters.
Word of the shooting first surfaced on Twitter.