By Jan Wolfe

WASHINGTON (Reuters) – The number of U.S. domestic terrorism cases under investigation by the FBI has more than doubled since spring 2020, its director told a Senate hearing on Tuesday, after the Justice Department warned that white supremacists and militias pose a growing threat.

“The domestic terrorism caseload has exploded,” FBI Director Chris Wray said during testimony before the U.S. Senate’s Homeland Security and Governmental Affairs Committee.

The bureau now has about 2,700 domestic terror investigations open, up sharply form about 1,000 in the spring of 2020, Wray said.

“To meet that evolving threat, the FBI has surged resources to our domestic terrorism investigations in the last year, increasing personnel by 260%,” Wray said.

Domestic terrorism took on new urgency after the Jan. 6 assault on the Capitol by supporters of then-President Donald Trump who were trying to overturn President Joe Biden’s election victory.

U.S. Attorney General Merrick Garland said the Jan. 6 attack by Trump supporters had shown white supremacists and militia groups to be the country’s greatest domestic security threat.

In June, Biden’s administration released a 30-page plan to counter domestic terrorism. It calls for increased information sharing between federal and local officials and social media companies, additional resources to identify and prosecute threats and new deterrents to prevent Americans from joining dangerous groups.

(Reporting by Jan Wolfe; Editing by Scott Malone and Lisa Shumaker)