The decomposing bodies of 20 men, bound and shot, have been found in a shallow grave near Baghdad, Iraqi police say.
The men, aged between about 15 and 50, are thought to have died weeks ago.
Police have not been able to identify the bodies because of their physical state, and no identification was found at the scene, a police spokesman said.
Correspondents say there has been an increasing number of unexplained murders in and around Baghdad, with bodies frequently dumped by the road.
The bodies were apparently found in the Nahrawan area east of the capital, after a tip-off from local people.
The police say they moved in to an abandoned firing range, once used by Saddam Hussein's army.
At first they saw nothing, but when they brought in bulldozers they uncovered the bodies of the men who, according to police, had been bound, shot and then hastily buried in a shallow grave.
The discovery was made in an isolated spot but mysterious killings are no longer an isolated phenomenon, says the BBC's Caroline Hawley in Baghdad.
The unexplained murders have been fuelling tensions between Sunnis and Shias, our correspondent adds.
A group of Sunni Muslim clerics says relatives have claimed the body of one of the dead men and that he was Sunni.