In response to a question from a journalist as he left his Castel Gandolfo secondary residence, the leader of the world's Catholics said a country had the right to have its military "defend peace".

"In this case, however, it seems a bit different. It increases tension," said the 70-year-old pope, speaking of reports of US boats "each time ever closer to the coast of Venezuela".

"I think that with violence we don't win. The thing to do is to seek dialogue," he added.

Trump has launched a major military deployment in the Caribbean in recent weeks, conducting multiple strikes on alleged drug-trafficking vessels, killing dozens.

He has downplayed potential US intervention in Venezuela, where leader Nicolas Maduro -- who faces indictment on drug charges in the United States -- has accused him of wanting to impose "regime change" in Caracas to seize Venezuelan oil.

The Chicago-born pope was also asked about migrants in detention in his home city -- America's third-largest -- which has been a key target of Trump's crackdown on immigrants.

"Jesus says very clearly at the end of the world, we're going to be asked, how did you receive the foreigner, did you receive him and welcome him or not," said the pontiff.

"I think there is a deep reflection that needs to be made in terms of what's happening. Many people who have lived for years and years and years never causing problems have been deeply affected by what's going on right now," he said.

In September, Leo -- a former missionary in Peru -- criticised what he called the "inhuman treatment" of immigrants in the US.