FBI 'foiled IS-inspired attacks on US Independence Day'

Suspects inspired by so-called Islamic State militants were planning attacks in the United States on July 4, the FBI has revealed.

FBI director James Comey said authorities had managed to thwart a number of plots being drawn up for America's national Independence Day holiday.

More than 10 people inspired by the militant extremists' recruitment campaign online have been arrested over the past four weeks, he said, with some of them focused on that specific date.

Local law enforcement agencies were put on alert for any terrorist activity - but in the end, the day passed without incident.

Comey would not confirm the number of plots uncovered or the potential targets, but said dozens of people suspected of being involved with the extremist group were exploiting encrypted data to "go dark" to try to avoid detection.