UK insurer Steamship Mutual has issued a warning to members over trading with Venezuela.
The move comes after an apparent widening of US sanctions against the South American country to include shipping oil to Cuba - and potentially elsewhere.
Greek operator Proper In and its 72,000-dwt tanker Despina Andrianna (built 2000) were blacklisted last week over alleged shipments from Venezuela to Cuba, which is seen as being supportive of president Nicolas Maduro's regime.
"The sanctions risks associated with trade involving Venezuela, particularly petroleum, have escalated in light of recent actions by OFAC [US Treasury Department's Office of Foreign Assets Control]," it said.
Steamship added: "There are no specific prohibitions against this trade, so it appears that that OFAC is willing to treat the executive order expansively and use it to sanction non-US persons in relation to a range of activities which support the Maduro regime."
It cited a recent US state department briefing by the US special representative for Venezuela, Elliot Abrams, as suggesting that the purchase of petroleum products from, or the supply of petroleum products to, Venezuelan oil company PDVSA would expose persons involved in those activities to sanctions risks.
Abrams said: “We have had conversations with foreign oil traders, with foreign governments, really along the same lines – that is, you should be supporting interim president Guaido, you should not be supporting this regime, you should not be buying oil from this regime and giving them cash.
"And we’ve noted that we have a wide, broad net with our sanctions, and so we’ve warned people, be careful not to get caught in that net by activities that you may think don’t come into it but actually are caught by it”.
