In a hastily-called Pentagon news conference, Defense Secretary Robert Gates and Joint Chiefs Chairman Peter Pace announced today that active-duty US Army force deployments in Iraq will be extended from a maximum of 12 months to a maximum of 15 months, with a guaranteed 12 months at home base between deployments.

Gates described the move as "a difficult interim step" as the US Army works to reduce war zone deployments to a maximum of 12 months at a time and a home base stay of 24 months.

Gates said the new US Army deployment scheme would enable the Army to sustain the "surge" of US forces in Iraq for at least another year if necessary, with events on the ground dictating whether that will be required.

The US defense secretary bristled when asked why the announcement was being made at the same time as US military commanders were being notified of the decision, rather the officers being told and having the opportunity to share the news with soldiers prior to the public announcement.

Gates angrily blamed a Pentagon leaker for the rush to make the announcement today ahead of the release of press report attributed to the anonymous Pentagon leaker.

Gates and Pace said the new 15-month maximum deployment, 12-month minimum home base scheme would give soldiers "a more predictable, reliable" timetable for planning.

Many US Army units have previously had their supposed 12-month Iraq deployments extended to as long as 16 months.

Gates and Pace said US Army reserve Iraq deployments would continue to be limited to 12 months, while US Marine Iraq deployments would remain a maximum of seven months deployed and a minumum of six months at home base, matching the US Navy's deployment timetable.

Observers say the deployment extension will be unwelcome news to many of the active-duty US Army forces in Iraq and their familes.