Fastexy Exchange|Manhunt underway for child sex offender who escaped from hospital

A manhunt is Fastexy Exchangeunderway for a convicted child sex offender who escaped custody while receiving treatment at a St. Louis hospital, authorities said.

Tommy Wayne Boyd, 45, an inmate from Potosi Correctional Facility, is serving a 30-year sentence for enticement of a child, online inmate records show.

He was receiving medical treatment at Mercy Hospital South when he walked out of the hospital, according to the St. Louis County Police Department. Boyd was last seen by hospital staff at 3:54 a.m. local time Thursday, police said.

"Surveillance video shows Boyd leaving the hospital on foot, traveling in an unknown direction," St. Louis County police said in a statement.

Two Missouri Department of Corrections officers were guarding Boyd when he escaped and there was no physical confrontation, the hospital said.

"Police searched campus and our security team searched all buildings on campus and found no evidence he is still here," Mercy Hospital said in a statement. "We continue to assist St. Louis County Police in their search and investigation."

The Department of Corrections is investigating how Boyd managed to escape, St. Louis County Lt. Col. Jason Law told reporters during a briefing Thursday.

Police said it is unknown if Boyd is armed but he should be considered "dangerous."

"We're urging residents to remain vigilant as our officers search for Mr. Boyd," police said on social media. "Be sure your homes and garages are secure. Watch children at bus stops."

Lindbergh Schools, a school district in the area of the hospital, said all of its schools are on "lockout" Thursday morning "out of an abundance of caution" amid the search. Schools will remain open, but all students and staff will remain indoors until further notice, the district said.

Law did not reveal details on the search area but said police are employing flight operations and canine units. The Missouri State Highway Patrol, state Department of Corrections and U.S. Marshals Service are assisting in the search, he said, adding that they have the resources to continue the search "indefinitely."

Boyd is listed on the state's sex offender registry after being convicted of statutory sodomy. The offense was committed in Springfield, Missouri, in 1996 when he was 18, online records show. The victim was an 11-year-old boy, according to the records.

Boyd is described by authorities as a 5-foot-7 white man weighing approximately 154 pounds with balding hair and a beard. He was last seen wearing a black sweatshirt, black jacket and orange slippers.

Anyone with information on the incident is urged to contact 866-371-8477.

ABC News' Victoria Arancio contributed to this report.