Client requesting scanned passport and signed NDA

[sgsantos313]

Good afternoon,

I received an invitation to apply for a job. The client is an upwork plus client, has thousands of hours recorded and I googled the company and contact and it seems legit.

My only concern is that they asked me to sign an NDA (which I read is good according to upwork policy.) and to send them a scanned copy of my  US passport. They say it's because they represent government agencies in DC where they require me to be a US citizen to work, hence the passport as proof of citizenship.

Is this safe or what would you recommend?