New Delhi, Jan. 4 -- After President Trump said U.S. forces seized Venezuela's leader, the bureau offered no details on any FBI involvement.

WASHINGTON - The FBI declined to confirm whether any of its agents took part in the operation that resulted in the capture of Venezuela's president, Nicolas Maduro, a refusal that is now amplifying global scrutiny of what US President Donald Trump has described as a sweeping "air, land and sea" strike-and-seizure mission carried out on Venezuelan soil.

The bureau's silence, neither affirming nor denying a role, comes as allies and rivals alike question the legality of an intervention that has rapidly shifted from a political shock to a full-spectrum international crisis, with some leaders and legal...