The United States reportedly carried out an attack on a ship in the Caribbean on Thursday that did not cause the deaths of all passengers, two US officials told CNN. There are believed to be survivors among the crew, but their condition is unknown.

This was first reported by Reuters, citing a U.S. official who spoke on condition of anonymity.

If confirmed, the U.S. military has carried out at least six separate attacks on ships in the Caribbean, though Thursday’s attack has not been acknowledged by the Trump administration, unlike the previous five, and appears to be the first time it did not result in the instant deaths of all passengers.

In some cases, President Trump has posted videos of the attacks on Truth Social and claimed the vessels were carrying drugs, describing the deceased as “drug dealers.”

Some lawmakers have pushed back on the attacks, arguing the government needs permission from Congress to target drug cartels and that it has not provided sufficient evidence the ships are carrying narcotics.

However, the administration has justified the attacks arguing that the United States is engaged in a “non-international armed conflict” with drug cartels. “When they’re loaded with drugs, they’re sitting ducks, and all of those ships were,” the president told reporters Wednesday. The Trump administration has issued a classified legal opinion justifying lethal strikes against a sprawling, secret list of cartels and suspected drug traffickers. The opinion is significant, legal experts previously told CNN, because it appears to justify giving the president the power to designate drug traffickers as enemy combatants and summarily execute them without legal review. Historically, those involved in drug trafficking were considered criminals entitled to due process,and the Coast Guard intercepted drug trafficking vessels and arrested smugglers.

President Donald Trump said Wednesday he had also authorized the CIA to operate in Venezuela to stem the illegal flow of migrants and drugs from the South American country.

For his part, Nicolas Maduro has denied having ties to drug trafficking and accused the Trump administration of seeking regime change. Earlier this week, he said he was ready to declare a state of emergency in the face of U.S. “aggression” and gave himself additional powers should the United States “dare to attack.”