Kaine, a longtime proponent of Congress’ powers to declare war, filed the resolution late Thursday, a move that will force the Senate to take up the legislation after a 10-day waiting period. Sens. Adam Schiff, D-Calif., and Rand Paul, R-Ky., co-sponsored the plan.

Kaine said concerns about war in the Latin American region are growing.

“The pace of the announcements, the authorization of covert activities and the military planning makes me think there’s some chance this could be imminent,” Kaine told reporters.