New Delhi, Sep 22 (IANS): FBI Director Christopher Wray has warned that the Taliban takeover in Afghanistan could inspire a new wave of extremism in the US, The Hill reported.

Wray testified before the Senate Homeland Security and Governmental Affairs Committee that extremist groups have never stopped plotting attacks on US soil.

"We are concerned that, with developments in Afghanistan, among other things, that there will be more inspiration to the first bucket," Wray told the committee. "So I think we anticipate, unfortunately, growth in both categories as we look ahead over the next couple of years."

This comes as National Counterterrorism Center Director Christine Abizaid also testified to the committee that the terrorism threat to the country is less "acute" than it was two decades ago, the report said.

Abizaid also said that US officials have been monitoring how terror groups al Qaeda and ISIS could rebuild their forces and conduct an attack on the US.

"In the wake of our withdrawal, the question is, at what point does that regional threat build to a capability and intent that is focused externally and particularly focused on the homeland?" Abizaid said, as per the report.

"I would say from an intelligence community perspective, that's one of our highest priorities, is just to monitor and assess the degree to which those groups actually present an external threat."