Nikon this morning released a second press release regarding the status of employees and plants after the earthquake. One Sendai employee has now been confirmed dead, and three employees are unaccounted for. My sincerest condolences to the Nikon staff on this sad news.
The Sendai plant (which makes FX bodies) is considered "severely damaged" and not scheduled to re-open until the end of March. The other affected plants, including the lens plant, should all be in operation by tomorrow. However, due to the many unresolved issues (power, supply chain, etc.), Nikon is unable to say when full production will resume; there may shortages of some products due to this.
One thing I should mention: Nikon has been amongst the most financially transparent of the Japanese companies. They share unit volume sales numbers that other camera companies don't, they are quick to issue statements on anything that might impact company business, they do not appear to try to hide anything about the business fundamentals. So when they issue a press release like this, I take it at straight face value: they are scrambling to restore production as fast as they can, but they do not yet know how much production that will be.