FREMONT -- A "high-security alert" at an East Bay hospital Wednesday was the result of suspicious items found on its property, but police and officials said it is safe for people to be there.

Fremont police did not comment on the nature of the "suspicious items" found by Washington Hospital staff "several days ago" but did say Wednesday afternoon that it appears they were left behind accidentally by a patient who came to the hospital in an ambulance.

"That's the way it's leaning," Sgt. Jeff Campbell said.

The items were suspicious enough to touch off an investigation that initially included the FBI but no longer does, Campbell said. It did not warrant a response by a bomb squad, he said.

KTVU, citing a hospital alert that went out to staff, said the suspicious items were "components of an explosive device." Hospital spokesman Chris Brown confirmed a memo went out to hospital staff but did not comment about the KTVU report.

"No explosives were ever found," Campbell said to this newspaper. "As far as the components of a bomb? When I think of components for a bomb, I think of something that's ready to go. This was definitely not that. But some of the items were suspicious."

The hospital was operating normally on Wednesday, Brown said, though under strict security regulations.

"We don't want people who need to come here for care bypassing that care in any way over concerns they may have over this," Brown said. "Safety is our top priority, not only for the patients but for the doctors and caregivers and everyone involved here. That's why an email went out, to alert (staff)."

Campbell said the investigation is ongoing but said the items found were legal ones.

"We don't know if they were discarded property or left behind to scare somebody," he said.

Campbell said the items were found "several days ago," but that police were not alerted until Tuesday around noon.

Brown did not say how long the hospital expects to be under the high-security alert.

Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rderh.