Solution:
Install required PHP libraries. RHEL installation command ( with all required modules for WordPress):
sudo yum install php-bcmath php-cli php-common php-devel php-gd php-imap php-mbstring php-mcrypt php-mysqlnd php-odbc php-pdo php-pear php-pecl-geoip php-pecl-jsonc php-pecl-jsonc-devel php-pecl-zip php-pgsql php-process php-tidy php-xml php-xmlrpc
Install EPEL repos to update to latest PHP:
#CentOS 6 64Bit
sudo wget http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
sudo rpm -ivh epel-release-6-8.noarch.rpm
sudo yum update php
EPEL repos installation process for other versions – How to Enable EPEL Repository for RHEL/CentOS 7.x/6.x/5.x
EDIT 1:
In order to disable other repositories, see and edit .repo files in /etc/yum.repos.d/ directory and set enabled=1 to enabled=0. After all don’t forget to run:
yum clean all