The Pentagon plans to spend an additional $900 million in the coming year to boost cyber defense measures, Defense Secretary Ashton Carter said Thursday.

US officials are still reeling from last year's revelation that personal data from some 20 million federal employees, contractors and others had been hacked in a massive breach at the Office of Personnel Management.

The military worries about being targeted by an array of hackers, including national adversaries such as North Korea and non-sovereign players like the Islamic State group.

"Given the increasing severity and sophistication of the threats and challenges we're seeing in cyberspace -- ranging from (IS's) pervasive online presence to the data breaches at the Office of Personnel Management -- the budget puts a priority on funding our cyber strategy," Carter said in a written statement to the House Appropriations Committee.

The Pentagon will spend a total of $6.7 billion in the 2017 budget -- up 15.5 percent from the previous year. In all, the Pentagon is projected to spend $34.6 billion over the coming five years.

Carter said the spending reflected the Pentagon's commitment to deterring "even the most advanced adversaries" and noted that the budget also invests in cyber warfare capabilities, including building potential cyber "military response options."

The risk of cyber attacks is noted as significant in the latest intelligence reports, Director of National Intelligence James Clapper told lawmakers on Thursday.

"Devices, designed and fielded with minimal security requirements and testing, and an ever-increasing complexity of networks, could lead to widespread vulnerabilities in civilian infrastructures and US government systems," Clapper told the US House Intelligence Committee.