President Donald Trump offered a head-turning defense of one of the most controversial moves made by his administration to take on drug cartels. 

Speaking with Fox News' host Trace Gallagher Tuesday, the President doubled down on his support of drug boat strikes and said he rendered their jobs unfillable. 

'They're carrying massive amounts of fentanyl, and that's an occupation that's very hard to fill right now. Nobody does it. Nobody would have done what I did,' Trump said.

He claimed drugs arriving by sea had fallen 'over 97 percent' and said his administration had now begun 'a very heavy push' against overland smuggling routes through Mexico, which he called far easier for cartels to exploit.

'We know every boat that's coming in. We know who it is and what's on that boat, and it's largely fentanyl and other really bad drugs,' he said.

Moments later Trump offered a different figure, saying his team had driven the numbers down '67, 68 percent' when experts had expected two or three per cent at best. He did not explain the gap between the two claims.

The strikes began on September 2 last year and have killed more than 200 alleged traffickers across the Caribbean and eastern Pacific, according to US Southern Command. 

The administration says it is in an 'armed conflict' with cartels, but has released little evidence that those killed were smuggling drugs bound for America.

The campaign's legality is still under investigation on Capitol Hill. 

The very first strike killed nine men, then a second attack ordered by Admiral Frank 'Mitch' Bradley killed two survivors clinging to the wreckage. 

Democrats and legal experts have called it murder. Republicans, including Senator Tom Cotton, say the men were still in the fight.

Secretary of War Pete Hegseth left Democrats furious after a closed-door Senate briefing in December when he refused to let all members of Congress view the unedited video, telling Chuck Schumer only: 'We have to study it.'