"We do not spend our time listening to the telephone calls or reading the emails of the majority," GCHQ boss Sir Iain Lobban told the committee.
More top news
Three women and three girls were reportedly shot dead because they were trailing 100 metres behind IS fighters.
Building a third runway at Heathrow was the most controversial of the three expansion options, so why is it going ahead?
The body of toddler Norma Dale was found dumped on wasteland near her home in 1946 with one of her red shoes missing.