World Health Organization (WHO) has decided to shut its offices down for indefinite period over security concerns. Sources at WHO told a private TV channel that all operations would remain suspended until the security of the polio staff is guaranteed. The World Health Institute in Karachi has also suspended polio monitoring. This is the first time in history that polio service to any city has been put off. WHO sources said that the decision to restore polio services would be taken when the circumstances normalize.