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.

Shareholders in Careem, whose backers include Saudi Prince Alwaleed bin Talal’s investment firm and Japanese e-commerce company Rakuten Inc., have been asked to agree to the terms of the transaction by Monday evening.

Careem was valued at about $1 billion in a 2016 funding round, making it one of the most valuable technology startups in the Middle East. The company has over a million drivers and operates in more than 90 cities in 15 countries, according to its website. For Uber, a deal would signal its commitment to the Middle East, where one of its biggest investors—a Saudi Arabian sovereign wealth fund—is based.