(Adds quote from export control lawyer; company names)

WASHINGTON, Oct 27 (Reuters) - The U.S. has stopped issuing export licenses for most civilian firearms and ammunition for 90 days for all non-governmental users, the Commerce Department said on Friday, citing national security and foreign policy interests.

The Commerce Department did not provide further details for the pause, which also includes shotguns and optical sights, but said an urgent review will assess the "risk of firearms being diverted to entities or activities that promote regional instability, violate human rights, or fuel criminal activities."

The Commerce Department declined to comment beyond the posting on its website.

The halt covers most of the guns and ammunition that could be purchased in a U.S. gun store, said Johanna Reeves, a lawyer who specializes in export controls and firearms with the law firm Reeves & Dola in Washington.

Reeves said she had not seen the Commerce Department take such a sweeping action like this before. "For sure they have individual country policies – but nothing like this," she said.

Export licences for Ukraine and Israel, as well as some other close allies, will be exempted from the temporary halt in exports.

U.S. companies that sell firearms, including Sturm Ruger & Co., Smith & Wesson Brands and Vista Outdoor , could be impacted by the export ban.

Overseas customers include distributors and stores that sell firearms.

Exporters can continue to submit license requests during the pause, but they will be "held without action" until the pause is lifted.

The pause does not affect previously issued export licenses, Commerce said.

For shipments to government clients, exporters must name specific end users, while applications with unnamed government, military, and police users will be "returned without action." (Reporting by Chris Sanders and Karen Freifeld; Editing by Sandra Maler)