Vladimir Putin will take part in an informal meeting of CSTO heads of state 2013-05-26 12:00:00 Vladimir Putin will take part in an informal meeting of the Collective Security Treaty Organisation (CSTO) heads of state on May 28 in Bishkek. It is planned that the meeting participants will discuss topical international and regional problems during their talks, as well as the prospects for further allied cooperation within the Organisation. A number of bilateral meetings is also scheduled to be held on the sidelines of the informal summit.