WASHINGTON (Reuters) - U.S. federal courts can operate through Jan. 31 despite a partial government shutdown, but warned they will not have funds to operate as normal beyond Feb. 1, officials said in a statement on Tuesday.

The Administrative Office of the U.S. Courts, which oversees operations for the federal district and appeals courts, revised its estimate as to when it will exhaust available funds from Jan. 25 to Jan. 31 after using a “strategy of deferring non-critical operating costs and utilizing court filing fees and other available balances.”

After Feb. 1, the courts could still conduct limited “mission critical work,” it said, but added that no further extensions of normal operations are possible.

The statement noted that courts and federal public defender offices have delayed or deferred expenses like new hires, non-case related travel and some contracts.

Since the shutdown began, courts have suspended or postponed some civil cases in which the government is a party, but have ordered others to go forward.