LONDON (AP) — London's preparations for hosting the 2017 world track and field championships have been hit by the sudden departure of its chief organizer.

U.K. Athletics says Sally Bolton, managing director of the organizing committee of the championships, is leaving for "personal reasons."

Bolton did not expand on the reasons, only saying she is "incredibly proud of the work that has been completed in achieving the early milestones that lay the foundations for the events success."

No replacement for Bolton was announced.

London won the bid to stage the championships in a 2011 vote. The event will be held at the Olympic Stadium.