The Night to Honour Israel and the John Hagee Ministries London Conference events were set for next week in Westminster with more than a thousand already registered.
A statement on John Hagee Ministries website explained the organisation had already planned to step up security in preparation for the conferences but received independent advice to postpone the events.
The statement read in part: "Islamic extremists have called for the specific targeting of Christians and Jews during the month of Ramadan, during which our events were set to take place.
"Although no specific threat has been received, we have been advised that our events could be targets.
"It is with wisdom and not fear that the leadership takes this responsibility for the protection of those that would attend, bearing in mind the Night to Honour Israel would be the largest pro-Israel event of the year with both Christians and Jews meeting at a location just a short distance from the two recent London attacks."
The organisation has offered refunds for those who already purchased tickets.
