US shutdown 'hurts military credibility with allies'

US Defense Secretary Chuck Hagel speaks to the press about the government shutdown in Seoul on October 1, 2013 (POOL/AFP)

Defense Secretary Chuck Hagel warned Tuesday that the US federal government shutdown raised a "dark cloud of uncertainty" over overseas military missions that would raise doubts among key allies.

Even though uniformed military personnel have been exempted and will continue to be paid, the shutdown directive would inevitably damage US credibility, Hagel told reporters in Seoul, where he is on the first leg of a visit to South Korea and Japan.

The trip is largely aimed at underscoring the US commitment to its two most important military alliances in the region, and Hagel said the "completely irresponsible" stance of the US Congress could only undermine that effort.

"This dark cloud of uncertainty... affects our missions around the world. It affects our allies questioning our commitment," he said.

While the shutdown will have no actual impact on US military treaty obligations, "it does cast a very significant pall over America's credibility to our allies", he added.

Hagel said lawyers at the Department of Defense were trying to work out if there was any room to expand the number of non-uniformed personnel exempted from the mass furloughs.