Dubai (CNN Business) Uber is buying the biggest ride-hailing app in the Middle East.

In the biggest tech deal the region has ever seen, Uber is paying $3.1 billion for Careem with a mixture of cash and securities that will convert into Uber shares when the company goes public.

Careem, based in Dubai, was founded in 2012 and has since become the regional market leader with 30 million users across 90 cities in the Middle East, North Africa and Pakistan. It was valued at more than $2 billion in a funding round in October.

Careem will operate under its own brand as a subsidiary of Uber and continue to be led by CEO Mudassir Sheikha, the companies said in a statement Tuesday.

In an email to Uber staff members seen by CNN Business, CEO Dara Khosrowshahi said keeping the Careem brand and operations "has the advantage of letting us build new products and try new ideas across not one, but two, strong brands."