SAO PAULO, July 27 (Reuters)

Two Iranian ships stranded for weeks at a Brazilian port will be able to set sail on Saturday after the firm chartering the vessels obtained court rulings obliging state oil company Petroleo Brasileiro SA to refuel them.

The ships were stranded after Brazil's state oil company, also known as Petrobras, refused to sell them bunker fuel in the wake of U.S. sanctions against Iran..

The refueling of one ship, the Bavand, started at around 5 a.m. local time and that vessel is expected to depart at 9 p.m. and head directly to Iran with a load of corn, a spokeswoman for the union of harbor pilots, Sinprapar, told Reuters by telephone.

According to the union, the refueling of the other ship, the Termeh, began at 1 a.m. and that vessel is expected to move at 1 p.m., bound for the port of Imbituba, where it is supposed to be loaded with corn for export.

On Friday, Petrobras Chief Executive Roberto Castello Branco told Reuters in an interview that the company would obey a Supreme Court order to refuel the Iranian grain vessels.

The refueling marks the end of a longstanding impasse sparked by Petrobras' refusal to refuel the bulk carriers, said law firm Kincaid Mendes Vianna, which represents the company that chartered the ships.

The Iranian vessels had been at the port of Paranaguá for more than 50 days, the law firm said in a statement on Saturday, and will this weekend return to Iran carrying a total load of 100,000 tonnes of corn worth about 100 million reais ($26.5 million) ($1 = 3.7749 reais) (Reporting by Ana Mano in São Paulo and and Marta Nogueira in Rio de Janeiro Writing by Ana Mano Editing by Matthew Lewis)