Will a company offering you a job ask for refundable security deposit to issue your visa?

A company in the UAE is requesting a refundable security deposit fee before giving a visa for a 2-year contract. I have applied through an agent, based in the UAE.

I got my job offer letter and the visa application is under process after filling out my visa form now I received an email from the company requesting for security fee deposit that can be refunded back to my account upon arrival in the UAE.

Is it legal or a scam?