Kazakhstan's President Nursultan Nazarbayev has left for Yerevan to participate in an informal summit of the Collective Security Treaty Organization (CSTO), Kazakh presidential press service reported.  

An informal meeting of the CSTO leaders with participation of organization’s Secretary General Nikolay Bordyuzha is scheduled for August 20 evening.

As NEWS.am reported earlier, after the meeting CSTO leaders will issue a statement followed by Nazarbayev’s meeting with Kyrgyz leader Roza Otunbayeva.