President Donald Trump announced Tuesday that the U.S. military conducted a strike on a suspected drug-smuggling vessel off Venezuela’s coast, killing six people linked to narcoterrorist networks.

The operation marks the fifth fatal strike against alleged drug boats in the Caribbean since September and follows the administration’s declaration of a “non-international armed conflict” with drug traffickers.

A new Joint Task Force under U.S. Southern Command was recently formed to intensify counter-narcotics operations.

However, several lawmakers, including Sens. Adam Schiff and Tim Kaine, have questioned the legality of the strikes, arguing they lack congressional authorization under the War Powers Act, Fox News has reported.

Venezuela has condemned the attacks as attempts at “regime change” and has requested an emergency U.N. Security Council session to address what it calls U.S. aggression.