Despite a short-term deal to fund the federal government's operation and increase the debt ceiling, the United States should focus on solving its medium-term fiscal challenges, the International Monetary Fund (IMF) spokesman William Murray said Thursday.

The IMF welcomed the recent step taken by U.S. Congress to fund the government through Jan. 15 and lift the government's borrowing authority through Feb. 7, but "there needs to be a durable solution to the debt ceiling," he said at a regular press briefing.

The federal government was forced into the first shutdown in 17 years on Oct. 1 after U.S. Congressional Republicans tried to tie a government funding bill with changing President Barack Obama's signature healthcare law.

"The United States needs to come up with a clear medium-term plan for dealing with its fiscal challenges forward. That's the critical issue at the moment," Murray said.