Spain is threatening to damage tourism to Gibraltar by disrupting flights and imposing a €50 fee to cross the Spanish border.
Foreign minister Jose Manuel Garcia-Margallo said the Spanish government was considering a list of sanctions as tensions between the UK-owned Gibraltar and Spain escalated.
These include closing air space to disrupt flights and charging the fee to cross between Spain and the Rock.
The border charge would hit 30,000 travelers every day, including 10,000 Spanish citizens who work in the shops, hotels and bars on Gibraltar.
The latest threats from Spain follow a month of deepening tensions that began when Gibraltar authorities began building a reef to bar Spanish fishing boats.
Garcia-Margallo told a newspaper it was necessary to control the border tightly to curb smuggling and money-laundering.
By Linsey McNeill, TravelMole UK
