The Pentagon is advising all services to cancel temporary duty assignments for U.S. military personnel who are attending professional development schools until the government shutdown has ended.

Temporary duty, or TDY, orders allow soldiers, sailors, airmen and Marines to leave their units for several weeks or months to attend leadership and military skill courses.

While the details still have to be finalized, “my initial information is that TDY to Professional Military Education and Civilian Education System (regardless of location) should be canceled or terminated,” said Army spokeswoman Lt. Col. Alayne Conway, explaining that any exceptions for soldiers would require Department of the Army-level approval.

This means servicemembers will be ordered to return to their home units -- in most cases -- before they complete the course work at the school, according to Pentagon shutdown contingency guidelines.

This is the latest guidance to be released as the Pentagon struggles to predict how long this partial shutdown of the federal government will last.

There will be a few exceptions though, Pentagon officials said. TDY that’s in direct support of operations in Afghanistan may continue, officials said. Also, a soldier that began a course like Airborne School in September and is scheduled to graduate on Friday should be allowed to do so.

However, “if a soldier reported to a PME class on Sept. 25 for a six-month school, that soldier would be returned home,” Conway said.

The government officially shut down at midnight Monday after the Republican-led House of Representatives and the Democratic-led Senate failed to reach a compromise on a budget or continuing resolution to fund the government for fiscal 2014.

In addition to thousands of furloughs, the shutdown has also put all Guard and Reserve training, both monthly and annual, on hold until the government is back up and running, according to Army Reserve and National Guard Bureau officials.

On Tuesday, troops, civilians, contractors and their families started to witness the fallout following the first government shutdown since the mid-1990s.

Servicemembers reported to work on time Tuesday like any other day and are expected to work throughout the government shutdown. Civilians and contractors working for the Defense Department, who were deemed "non-essential," received furlough notices Tuesday morning and will not return to work until the shutdown ends.

All 16,000 civilian workers at the Pentagon were told to report to work Tuesday. Almost half were given furloughs and allowed four hours, for which they will be paid, to clean out their workspaces and turn in office gear, a Pentagon spokesman said.