AKIPRESS.COM - Spain proposed Friday sharing sovereignty over Gibraltar after Britain voted to leave the European Union, saying this could be a prelude to bringing the overseas territory back under its control, AFP reports.

The comments by acting Foreign Minister Jose Manuel Garcia-Margallo are likely to spark concern in the tiny rocky outcrop on Spain's southern tip, which has long been the subject of an acrimonious sovereignty row between London and Madrid.

"Our formula... is British-Spanish co-sovereignty for a determined period of time, which after that time has elapsed, will head towards the restitution of Gibraltar to Spanish sovereignty," Margallo told Spanish radio.

Spain wants Gibraltar back under its control centuries after it was ceded to Britain in 1713.

The country's conservative government, which has been in place since 2011 and is expected to win elections Sunday -- albeit without an absolute majority -- has been particularly vocal about its desire to see Gibraltar come back into its fold.

The Rock is now worried that it will be at the mercy of Madrid without the protection of the EU, which has had to intervene in the past to ease rows between the two.

Margallo said the issue of Gibraltar was no longer within the remit of the European Union, after Britons voted to leave the bloc in Thursday's referendum.

"It is now a bilateral issue that will be negotiated exclusively between the United Kingdom and Spain," he said, adding a solution would have to be found if Gibraltar wanted to keep its access to the EU's single market.

The Rock relies in large part on access to the single market for its thriving economy.

In a tweet, Gibraltar's Chief Minister Fabian Picardo called for calm. "We have surpassed greater challenges. It is time for unity, for calm & for rational thinking. Together & united we will continue to prosper," he said.

Gibraltarians turned out en masse to vote in the referendum Thursday, and 96 percent of those who cast their ballot voted to remain in the European Union.