President Donald Trump vowed a tough response to the bombings in Austin, Texas, decrying the actions as “very, very sick.”

“This is obviously a very, very sick individual or maybe individuals,” Trump said, vowing to get to the bottom of the crimes.

The president spoke to reporters at the White House about the attacks during a visit with Saudi Arabia’s crown prince Mohammed bin Salman. He said that federal law enforcement was already working with local officials to identify the source of the attacks.

“We have a lot of power over there, we’re looking, it’s not easy to find but these are sick people and we have to find them as soon as possible,” Trump said. “We have to produce.”

Trump made his comments after a device exploded inside a FedEx package facility early this morning near San Antonio. The explosion marked the sixth attack that is believed to be connected to the same source. Federal officials have concluded that it is likely that the bombs are the product of a “serial bomber.”

Trump added that it was “absolutely disgraceful” that the bombings targeted Austin, calling the city “a great place, a tremendous place.”