The United Kingdom has stopped sharing intelligence with the United States on drug-trafficking boats in the Caribbean, citing concerns that its information could be used to support U.S. military strikes it considers unlawful, CNN reported.

The report says the pause began over a month ago, with British officials agreeing with the international consensus that U.S. strikes on suspected drug boats in the Caribbean and eastern Pacific violate international law and amount to “extrajudicial killing.” 

The operation, which began in September, has killed at least 76 people. The most recent strikes occurred on November 10, when U.S. forces targeted two vessels in the eastern Pacific, killing six people.

In explaining the rationale behind the strikes, the Trump administration repeatedly claimed that the targets were “enemy combatants” linked to drug cartels deemed “foreign terrorist groups” engaged in an “armed conflict” with the U.S., and thus subject to the Law of Armed Conflict. Legal experts, however, said labeling a group as a foreign terrorist organization does not automatically authorize lethal force.

For years, the U.K., which maintains several Caribbean territories hosting intelligence assets, has assisted the U.S. in tracking vessels suspected of carrying drugs. The intelligence was usually forwarded to Joint Interagency Task Force South in Florida, a multinational effort aimed at curbing the illicit drug trade.

Canada has also reportedly warned Washington against using its intelligence for targeting operations. 

The British embassy in Washington and the White House did not respond to requests for comment.