Two FBI agents were shot near St. Louis, Missouri in Friday, but the incident was not "not directly related to the Ferguson protests," an FBI spokeswoman told NBC News.

The shooting, which occurred just after 3 a.m., may have been a case of "suicide by cop," the federal law-enforcement agency said.

The first FBI agent was shot in the shoulder, while the other was hit in the leg. Both were transported to a hospital to undergo surgery and are expected to be OK.

The two agents were assisting the University City Police Department execute an arrest warrant, according to The Associated Press.

University City, an inner-ring suburb of the city of St. Louis in St. Louis County, is less than half a dozen miles from Ferguson, which was a flashpoint of violence after the Nov. 24 grand jury decision not to indict police Officer Darren Wilson, who shot and killed black 18-year-old Michael Brown on Aug. 9.

In a tense environment, at least two dozen police and other emergency vehicles responded to Friday's shooting, USA Today noted. For example, Barnes-Jewish Hospital is reportedly heavily guarded with an FBI truck.

The incident may be related to an earlier shooting that occurred late Monday in University City in which a police officer was shot in the chest.

"Officers were summoned to a house around 10 a.m. in a residential area of the suburb of about 35,000 people," USA Today reported. "The caller said a man had climbed through a window and started shooting, (according to) the University City Police Department. Officers arriving at the home found Donna Washington, 55, with a gunshot wound to her leg."

Washington later died.

When three policemen approached the home, one was shot but was able to return gunfire, University City Police detective Sgt. Fredrick Lemons said.

"It was not immediately apparent whether the gunman, identified as Washington's son Major Washington, 33, was hit," USA Today reported. "The suspect was last seen running east toward a major thoroughfare about two blocks away."