The emerging Islamic State and similar extremist groups are pushing defense spending priorities to reflect a greater need for unmanned aerial systems and sensors, said Frank Kendall, the Pentagon's chief weapons buyer, according to a report in Defense News.

"There's probably some shift, but it's an increase in areas that were not as on the forefront before," Kendall told reporters on Sunday, at the start of the biannual IDEX show in Abu Dhabi.

The event comes a week after the US announced plans to loosen restrictions on armed drone exports. Kendall said unmanned systems are primarily an ISR tool, but do have some use in attacking targets.