BY ANDREW BLANKSTEIN and ALEXANDER SMITH, NBC News

The suspect in a spate of bombings that terrorized residents of Austin, Texas, died after detonating an explosive inside his vehicle as a SWAT team approached to apprehend him on the side of a highway, officials said.

Early Wednesday, authorities tracked the suspect — a 24-year-old white man — to a hotel in Round Rock, a city in the Austin metropolitan area, Austin Police Chief Brian Manley told a news conference early Wednesday.

They tracked his vehicle until it pulled over on Interstate 35 and the suspect "detonated a bomb inside the vehicle, knocking one of our SWAT officers back and one of our officers fired on the vehicle as well," Manley said.

The police, FBI, and personnel with the Bureau of Alcohol, Tobacco, Firearms and Explosives have been deployed to the section of the interstate where the incident happened, the ATF said in a tweet.

The Austin Police Department described it as an "officer-involved shooting" on a section of highway in Round Rock, a city in the Austin metropolitan area. It happened at around 2 a.m. local time (3 a.m. ET), according to NBC News affiliate KXAN.

The police investigation means the southbound lane of the highway would be closed for four hours while the northbound lane would remain open, it said.

Austin has been on edge after a series of packages or other bombs detonated across the city over the past few weeks.

The most recent of these occurred Sunday when two people were injured by a device believed to have used a tripwire.

Authorities have warned that the devices appeared to be getting more sophisticated and asked residents of one neighborhood to stay indoors Monday.

The FBI has sent 350 special agents to the Texas capital as well as extra bomb squads.

"We are clearly dealing with a serial bomber," Austin Police Chief Brian Manley said. "We will have to determine if we see a specific ideology behind this."