VIRGINIA BEACH, Va. — They were among the elite of the elite, members of the FBI’s paramilitary counterterrorism Hostage Rescue Team traveling the globe to respond to fast-developing criminal threats. The agents who died Friday off the coast of Virginia Beach, Va., were training for some of the most rigorous and dangerous law enforcement assignments.

Christopher Lorek, 41, of Glen Allen, Va., and Stephen Shaw, 40, who lived in Stafford County, Va., were mourned Monday by family, friends and thousands of colleagues. Authorities released no new details about how they died or what they were doing off the coast of Virginia when the accident occurred. Team members, who are expert marksmen, train to rappel from helicopters, scuba dive and parachute.

The Virginia Medical Examiner’s Office said it could be weeks before a cause of death is released for both agents.

The often secretive nature of their work was reflected Monday in the scant details released about the agents, not only about their work in the field, but in their lives at home. The pastor of Lorek’s church, where Lorek’s funeral service is scheduled for Wednesday, would only say that the family, including daughters age 8 and 11, “were active members from the day they hit Richmond.”

A neighbor of Lorek’s in a community of 14,000 northwest of Richmond would only say, “The family is very private. It’s just sad.”

The FBI said that Shaw is survived by his wife, 3-year-old daughter and 1-year-old son.

He lived on a quiet cul-de-sac in Stafford County. A man who identified himself as an FBI colleague said the family did not wish to speak publicly. The colleague, who also declined to comment, wore a black polo shirt embroidered with the FBI Hostage Rescue Team’s motto: “Servare Vitas.” The Latin phrase means “To save lives.”

Lorek joined the FBI in 1996; Shaw came in 2005. Joining the Hostage Rescue Team requires years of service and brutal training during which agents shed their identities to ensure each is judged equally. On the first day, applicants are awakened before dawn to climb stairs wearing 55-pound vests and carrying 35-pound battering rams.

And that, the FBI says on its website, is the easy part. Fewer than 300 agents have been selected to the team since it was formed 30 years ago. Members are prepared to deploy within four hours of an emergency on U.S. soil.

The Hostage Rescue Team, based at Quantico, Va., was formed in 1983. The Summer Olympic Games in Los Angeles were approaching, and fears remained after the 1972 Games in Munich, when Palestinians took 11 Israeli athletes hostage and killed them. The unit is not limited to rescuing hostages, but also terror threats and large-scale manhunts in extreme weather and habitat.

In 2011, the FBI team helped other special operations forces kill four sea pirates, one in close combat with a knife, who had commandeered a yacht off the coast of Somalia and killed the four Americans aboard, according to the FBI’s website. A member of the Hostage Rescue Team had been deployed from Nairobi, Kenya.

In February, the hostage team killed a truck driver who had taken a 5-year-old boy hostage in an underground bunker in Alabama for a week. The kindergarten student was pulled out unharmed as agents exchanged fire with his captor.

It could not be determined what missions Shaw or Lorek had performed. A person who answered the phone at Lorek’s house in Glen Allen said the family did not wish to speak about the agent. Calls to his parents and brother were not returned.

Lorek graduated in 1993 with a bachelor’s degree in ocean engineering from Texas A&M University, a school spokeswoman confirmed. Past jobs and various positions in the FBI were not disclosed, though published reports put Lorek as a field agent in Wisconsin in 2001.

An obituary notice distributed by Bliley’s Funeral Home says Lorek is survived by his wife, Jennifer; young daughters Abigail and Madeline; his parents, William and Janet Lorek; and his brother, Jason.

The FBI Agents Association, a professional group of nearly 12,000 active and retired agents, released a brief statement Monday saying, “The bravery and dedication of special agents Lorek and Shaw will not be forgotten.”