Проблема установки Composer

Когда я бегу composer install Команда Я получаю ниже проблему. Версия уже изменена в файле composer.json.

Problem 1
    - Installation request for doctrine/mongodb 1.1.6 -> satisfiable by doctrine/mongodb[1.1.6].
    - doctrine/mongodb 1.1.6 requires ext-mongo >=1.2.12,<1.6-dev -> the requested PHP extension mongo is missing from your system.
Problem 2  
    - doctrine/mongodb 1.1.6 requires ext-mongo >=1.2.12,<1.6-dev -> the requested PHP extension mongo is missing from your system.
    - doctrine/mongodb-odm 1.0.0-BETA10 requires doctrine/mongodb >=1.1.5,<2.0 -> satisfiable by doctrine/mongodb[1.1.6].
    - Installation request for doctrine/mongodb-odm 1.0.0-BETA10 -> satisfiable by doctrine/mongodb-odm[1.0.0-BETA10].