"We have full confidence in the London authorities to secure the games," IOC spokeswoman Giselle Davies said in Singapore on Thursday.
Davies said the IOC did not believe the attacks were related to the city winning the right to host the 2012 Games on Wednesday night at an IOC meeting in Singapore.
"This is not at all related to the Olympics," she said, adding
that the IOC was being given regular updates about events in London by members of the city's team bid members.
Among those still in Singapore were London Mayor Ken Livingstone, Olympic Minister Tessa Jowell and bid leader Sebastian Coe. They were to fly out of Singapore for London late on Thursday night.
"We have full confidence in the London authorities to secure the Games"
Davies said IOC President Jacques Rogge was contacting British Prime Minister Tony Blair and Livingstone to give them his "support and sympathy".
At least six blasts rocked London buses and underground railway lines on Thursday, leaving two people dead and scores injured in what Blair said were most likely a series of "terrorist attacks".