SAO PAULO/RIO DE JANEIRO (Reuters) - Two Iranian vessels have been stranded for weeks at Brazilian ports, unable to head back to Iran due to lack of fuel, which state-run oil firm Petrobras refuses to sell them due to sanctions imposed by the United States.

The vessels Bavand and Termeh came to Brazil a couple months ago carrying urea, a petrochemical product used as fertilizer. They were expected to load corn and return to Iran, but lacked enough fuel for the trip, the port operator in Paranaguل told Reuters.