Two deputy U.S. marshals and a police officer were wounded during a gunfight at a St. Louis home Tuesday, the latest in a series of shootings of federal agents who are facing what authorities say are increasing risks on the job.

One marshal was in critical condition and a second was in fair condition, according to Laura Keller, a spokeswoman for St. Louis University Hospital, where both were treated.

A St. Louis police officer was wounded in the shootings, which occurred as the three officers were serving an arrrest warrant, said Jeff Carter, spokesman for the U.S. Marshals Service.

At least one other man was wounded during the incident, which resulted in a standoff at the home, authorities said. Police had cordoned off several blocks near the house with police tape and blocked access with police cars and vans.

Earlier reports from the marshals service that one of the marshals had died were inaccurate, Carter said.

“Everything is still very sketchy,’’ said Schron Jackson, a St. Louis police spokeswoman.

The marshals service arrests fugitives and works with state and local law enforcement on regional fugitive task forces that target violent offenders. The police officer who was shot Tuesday was on one of those task forces, Carter said.

The incident follows the shooting deaths of two federal agents on successive days last month and highlights the heightened risk to federal investigators who are confronting increasingly violent fugitives, drug traffickers and other criminals. Among those killed in February was a deputy U.S. marshal in West Virginia, Derek Hotsinpiller, who was one of several officers serving an arrest warrant on a man wanted on federal drug and weapons charges.

A Border Patrol agent was also fatally shot in Arizona in December.

The killings, while not connected, come amid a broadening federal role in fighting violent crime that was once left mainly to state authorities, investigators have said. Federal-state task forces on violent crime have multiplied since the Sept. 11, 2001, attacks on the U.S., bringing federal agents in closer contact with dangerous criminals. And the government says it is pouring resources into fighting drug trafficking and other crimes along the border with Mexico.

Overall, deaths of officers in the line of duty are rising nationwide. About 160 died in 2010, a nearly 40 percent increase from the year before, according to the D.C.-based National Law Enforcement Officers Memorial Fund. The organization, which tracks law enforcement deaths, said 61 officers were killed by gunfire in 2010, up from 40 in 2008.