The Navy will delay maintenance on 11 ships due to the three-month stopgap budget passed by Congress last week, according to a Pentagon assessment provided to Congress Monday.

The delays caused by the continuing resolution, or CR, will have a cascading effect on Navy ship maintenance over the next year and could affect ship repair periods into fiscal 2019, the Pentagon said in the report to the Senate Armed Services Committee on Monday.

The report, which included a signed cover letter by Defense Secretary Jim Mattis, lays out a variety of wide-ranging effects as the military focuses on funding forward-deployed and combat forces at the expense of all other operations. The CR locks in spending at fiscal 2017 levels.

"Doing so imposes a great burden on DOD's foundational capabilities and immediately manifests in impacts on training, readiness and maintenance, personnel and contracting," the report found.

Mattis, in his cover letter, warned against a longer CR that would "impact the readiness of our forces and their equipment at a time when security threats are extraordinarily high" and urged Congress to use the time to eliminate caps on defense and other federal spending.

"In the long-term, it is the budget caps mandated by the Budget Control Act that impose the greatest threat to the department and to national security," he said.

The Navy had slated maintenance periods for the 11 ships — including five destroyers, three cruisers and a littoral combat ship — between November and February, but will be forced to delay the timeline. The service, which suffered two deadly collisions in the Pacific this summer, is also set to be hit with other changes that could also affect ship deployments.

A CR will reduce Navy aircraft flying hours and ship steaming days for any units that are not deployed or the next to deploy, as well as reduce maintenance operations.

"Although maintenance impacts can be mitigated for some activities operating under a three-month CR, in areas such as Navy Ship Depot Maintenance, funding shortfalls result in delays in naval vessel availability, which may affect subsequent deployment rotations," the Pentagon told the Senate committee.

The Army will see $400 million less funding per month under the three-month CR, which Congress passed as part of Hurricane Harvey relief aid and a suspension of the debt ceiling.

The service will be forced to defer buying supplies and "later have to pay more to get parts fabricated or shipped quickly," the Pentagon found.

The stop-gap budget will "immediately postpone all non-critical maintenance work orders until later in the year," it said.

Both the Air Force and the Marine Corps must now curtail training.

The CR forces the Air Force to cancel exercises and put off creating two additional training squadrons and growing its force, leaving it "unable to train the number of pilots necessary for continued readiness recovery."