In December, Spanish news agency Europa Press reported that the US administration had asked Spain, France and Italy for permission to dump chemical waste from Syria's Civil War in one of their ports in the Mediterranean.
"All they're looking for is a place to unload waste that has already been treated," Spanish government sources told Europa Press.
Catalan newspaper El Periódico has now reported that Prime Minister Mariano Rajoy was advised by Spain’s Head of National Security Alfonso Senillosa to reject the White House’s request to unload the chemical waste at Tarragona's port in Catalonia.
Obama and Rajoy are due to meet in Washington on January 13th, an encounter some Spanish media outlets are claiming will be used as a type of olive branch by the US president after a turbulent year in Spain-US relations.
In October, Spanish newspapers published information leaked by NSA whistleblower Edward Snowden suggesting the US had tracked millions of Spanish phone calls as part of a widespread spying campaign.
But Spain's version of the CIA - the CNI - then came out and said they had handed over the information to the US as part of a joint terrorism-fighting effort.
Whatever the outcome of Obama and Rajoy's meeting, El Periódico wrote on Thursday that one of the central talking points of their encounter will no doubt be Syria’s chemical waste.
"We will have to wait a few days to see if Rajoy's decision is irreversible," El Periódico wrote.