Police headquarters in Derry have confirmed that the Provisional I.R.A. have been using a rapid-fire automatic machine-gun in the city over the past ten days.
According to reports from Belfast the gun is of American make, superior to anything issued to the police, and it is alleged it has been imported through the Republic.
R.U.C. detectives and British army intelligence agents have been given high priority orders to find what is believed to be a number of guns in Northern Ireland.
The guns are said to be capable of firing 300 rounds of ammunition a minute.
The Derry police statement said that the gun was used in two recent attacks in Derry, one on an army fire-fighting source on January 13 and the other in an attack on two police land rovers at the junction of the Letterkenny Road and Lone Moor Road.