The Dallas Police Department stepped up security Saturday after an anonymous threat was made against law enforcement officers in the city, the department said.
Officers with body armor and long guns were seen outside Dallas police headquarters at around 5 p.m. local time (6 p.m. ET). Police did not disclose the nature of the threat or how it was made.
The police department said it was searching for a suspicious person in a parking garage used by police. An initial search found no suspect, but a police dog did a secondary search to make sure, the department said. By shortly before 8 p.m., the search ended and no suspicious person or items were found, police said.
The SWAT team set off a device in order to get through a locked fence, and the department stressed no shots were fired.
The threat was made two days after a lone gunman opened fire on police at a protest rally, killing five officers, in an attack that targeted law enforcement. Seven other officers and two civilians were wounded.
The gunman, Micah Johnson, an Army veteran, was killed by a bomb delivered by police during a standoff with officers after the ambush.
The protest rally was held following recent fatal police shootings of black men in Louisiana and Minnesota.
People have left a memorial of flowers, balloons and signs on a police car outside the Dallas Police Department in a show of support for police officers following the deadly attack.